scholarly journals Optimisation of wastewater treatments through combined geomaterials and natural soil filter: modelling tools

2012 ◽  
Vol 2 (4) ◽  
pp. 185-193 ◽  
Author(s):  
M. Pettenati ◽  
N. Croiset ◽  
G. Picot-Colbeaux ◽  
J. Casanova ◽  
M. Azaroual ◽  
...  
Keyword(s):  
Transport Model ◽  
Soil Column ◽  
Pyrite Oxidation ◽  
Experimental Results ◽  
Treated Wastewater ◽  
Reactive Flow ◽  
Natural Soil ◽  
Engineering System ◽  
Flow Through ◽  
Anaerobic Environment

The main objective of this study is the establishment of innovative purification systems through the conceptualisation of reactive barriers in soil for artificial recharge of groundwater with treated wastewater. Numerical integration of hydrodynamics and biogeochemical processes controlling the effectiveness of this engineering system is applied to design soil column experiments. This leads to the elaboration of a combined aerobic/anaerobic environment to ensure the successive nitrification of rich ammonium wastewater and the denitrification mechanisms reducing NO3– according to heterotrophic denitrification and pyrite oxidation. A MIN3P reactive flow and transport model is used to reproduce an experimental flow-through column. Calculated concentrations of CH2O and NO3− are consistent with experimental results. Agreement between model and experimental results makes it possible to understand major processes taking place in the column and optimises future treatment experiments.

scholarly journals Perchlorate and Agriculture on Mars

Soil Systems ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Christopher Oze ◽  
Joshua Beisel ◽  
Edward Dabsys ◽  
Jacqueline Dall ◽  
Gretchen North ◽  
...  
Keyword(s):  
Plant Growth ◽  
Soil Column ◽  
Metal Availability ◽  
Metal Release ◽  
High Solubility ◽  
Plant Life ◽  
Growing Medium ◽  
Successful Removal ◽  
Flow Through ◽  
Martian Regolith

Perchlorate (ClO4−) is globally enriched in Martian regolith at levels commonly toxic to plants. Consequently, perchlorate in Martian regolith presents an obstacle to developing agriculture on Mars. Here, we assess the effect of perchlorate at different concentrations on plant growth and germination, as well as metal release in a simulated Gusev Crater regolith and generic potting soil. The presence of perchlorate was uniformly detrimental to plant growth regardless of growing medium. Plants in potting soil were able to germinate in 1 wt.% perchlorate; however, these plants showed restricted growth and decreased leaf area and biomass. Some plants were able to germinate in regolith simulant without perchlorate; however, they showed reduced growth. In Martian regolith simulant, the presence of perchlorate prevented germination across all plant treatments. Soil column flow-through experiments of perchlorate-containing Martian regolith simulant and potting soil were unable to completely remove perchlorate despite its high solubility. Additionally, perchlorate present in the simulant increased metal/phosphorous release, which may also affect plant growth and biochemistry. Our results support that perchlorate may modify metal availability to such an extent that, even with the successful removal of perchlorate, Martian regolith may continue to be toxic to plant life. Overall, our study demonstrates that the presence of perchlorate in Martian regolith provides a significant challenge in its use as an agricultural substrate and that further steps, such as restricted metal availability and nutrient enrichment, are necessary to make it a viable growing substrate.

Experimental Study on the Optimal Thickness of Infiltration Media of the CRI System

2011 ◽  
Vol 415-417 ◽  
pp. 1703-1707
Author(s):  
Jun Min Chen ◽  
Xiao Lin Yao
Keyword(s):  
Experimental Study ◽  
Removal Efficiency ◽  
Significant Influence ◽  
Soil Column ◽  
Experimental Results ◽  
Artificial Soil ◽  
Optimal Thickness ◽  
Effluent Quality ◽  
Anaerobic Zone

Abstract. In order to investigate the optimal thickness of infiltration media in the Constructed Rapid Infiltration System, the artificial soil column is used to simulate the Constructed Rapid Infiltration System, and the CODCr, NH3-N and TN concentrations of the effluent from all the sampling sites are monitored. The experimental results and analysis show that the thickness of infiltration media exerts a significant influence on the CODCr, NH3-N and TN concentration and removal efficiency of the effluent; the CODCr, NH3-N and TN are mainly removed in the 0-1800mm zone of the artificial soil column; the total CODCr removal efficiency increases, as the thickness of infiltration media increases, but the CODCr removal efficiency in the 1800-2200mm zone is very low; the NH3-N and TN removal efficiency reaches the maximum where the thickness of infiltration media is 1800mm; the NH3-N and TN concentration of the effluent from 1800-2200mm zone dose not decrease, but increase 5-8%, due to the assimilation denitrification and amemoniation reaction on the end of the anaerobic zone; in consideration of the effluent quality, efficient biodegradation zone, construction investment, etc. the optimal thickness of infiltration media in CRI system should be 1800mm.

scholarly journals Mineralogical, numerical and analytical studies of the coupled oxidation of pyrite and coal

2003 ◽  
Vol 67 (2) ◽  
pp. 381-398 ◽  
Author(s):  
K. A. Evans ◽  
C. J. Gandy ◽  
S. A. Banwart
Keyword(s):  
Reactive Transport ◽  
Transport Model ◽  
Pyrite Oxidation ◽  
Spoil Heap ◽  
Reaction Fronts ◽  
Order Of Magnitude ◽  
Magnitude Variation ◽  
Discharge Chemistry ◽  
Analytical Expressions

Mineralogical, bulk and field leachate compositions are used to identify important processes governing the evolution of discharges from a coal spoil heap in County Durham. These processes are incorporated into a numerical one-dimensional advective-kinetic reactive transport model which reproduces field results, including gas compositions, to within an order of magnitude. Variation of input parameters allows the effects of incorrect initial assumptions on elemental profiles and discharge chemistry to be assessed. Analytical expressions for widths and speeds of kinetic reaction fronts are developed and used to predict long-term development of mineralogical distribution within the heap. Results are consistent with observations from the field site. Pyrite oxidation is expected to dominate O2 consumption in spoil heaps on the decadal timescale, although C oxidation may stabilize contaminants in effluents on the centennial scale.

scholarly journals Implementing the Water, HEat and Transport model in GEOframe (WHETGEO-1D v.1.0): algorithms, informatics, design patterns, open science features, and 1D deployment

2022 ◽  
Vol 15 (1) ◽  
pp. 75-104
Author(s):  
Niccolò Tubini ◽  
Riccardo Rigon
Keyword(s):  
Land Surface ◽  
Design Patterns ◽  
Transport Model ◽  
Soil Column ◽  
Land Surface Model ◽  
Richards Equation ◽  
Energy Budgets ◽  
Programming Approach ◽  
Generic Programming ◽  
Surface Model

Abstract. This paper presents WHETGEO and its 1D deployment: a new physically based model simulating the water and energy budgets in a soil column. The purpose of this contribution is twofold. First, we discuss the mathematical and numerical issues involved in solving the Richardson–Richards equation, conventionally known as the Richards equation, and the heat equation in heterogeneous soils. In particular, for the Richardson–Richards equation (R2) we take advantage of the nested Newton–Casulli–Zanolli (NCZ) algorithm that ensures the convergence of the numerical solution in any condition. Second, starting from numerical and modelling needs, we present the design of software that is intended to be the first building block of a new customizable land-surface model that is integrated with process-based hydrology. WHETGEO is developed as an open-source code, adopting the object-oriented paradigm and a generic programming approach in order to improve its usability and expandability. WHETGEO is fully integrated into the GEOframe/OMS3 system, allowing the use of the many ancillary tools it provides. Finally, the paper presents the 1D deployment of WHETGEO, WHETGEO-1D, which has been tested against the available analytical solutions presented in the Appendix.

scholarly journals M4EKR, Multiphysics for ElectroKinetic Remediation of Polluted Soils

2020 ◽  
Vol 195 ◽  
pp. 02003
Author(s):  
Ángel Yustres ◽  
Rubén López-Vizcaíno ◽  
Virginia Cabrera ◽  
Vicente Navarro
Keyword(s):  
Reactive Transport ◽  
Natural Waters ◽  
Transport Model ◽  
Numerical Models ◽  
Electrokinetic Remediation ◽  
Natural Soil ◽  
Algebraic Equations ◽  
Advective Flow ◽  
Partially Saturated Soils ◽  
2,4 Dichlorophenoxyacetic Acid

Electrokinetic soil remediation (EKR) is one of the most promising techniques for decontamination of low permeability soils, in which the most classical techniques have been found to be less efficient. However, its practical application on a real scale has been rather limited since the phenomena involved in these processes are very complex. For this reason, it is essential to use numerical models that allow us to know the main trends in the behaviour of soils and natural waters subjected to EKR processes. This study presents the numerical model M4EKR (Multiphysics for ElectroKinetic Remediation). The M4EKR module is a reactive transport model for partially saturated soils that allows reproducing the transport of species due to electroosmosis, electromigration, diffusion and advective flow. The model was completely implemented in COMSOL Multiphysics, a partial differential equation solver. The system of differential and algebraic equations to solve the chemical and transport problem was fully defined by the authors, and they were solved by the M4EKR module in COMSOL (monolithic approach). The scope of the model is illustrated by simulating an EKR process of a natural soil and porewater contaminated with a polar pesticide: 2,4-Dichlorophenoxyacetic acid. For simplicity, the M4EKR version used in this study does not include gas transport, it does not consider the deformability of the soil and it is assumed the processes occur under isothermal conditions.

Meta-Analysis of Gas Flow Resistance Measurements Through Packed Beds

1995 ◽  
Vol 117 (1) ◽  
pp. 176-180
Author(s):  
Malcolm S. Taylor ◽  
Csaba K. Zoltani
Keyword(s):  
Reynolds Number ◽  
Statistical Methods ◽  
Flow Resistance ◽  
Gas Flow ◽  
Meta Analysis ◽  
Experimental Results ◽  
Packed Beds ◽  
Flow Through ◽  
Effective Representation ◽  
Number Of Authors

Measurements of the resistance to flow through packed beds of inert spheres have been reported by a number of authors through relations expressing the coefficient of drag as a function of Reynolds number. A meta-analysis of the data using improved statistical methods is undertaken to aggregate the available experimental results. For Reynolds number in excess of 103 the relation log Fv = 0.49 + 0.90 log Re′ is shown to be a highly effective representation of all available data.

Forced Convection in a Porous Channel With Discrete Heat Sources

2000 ◽  
Vol 123 (2) ◽  
pp. 404-407 ◽  
Author(s):  
C. Cui ◽  
X. Y. Huang ◽  
C. Y. Liu
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Porous Channel ◽  
Heat Sources ◽  
Nusselt Numbers ◽  
Discrete Heat Sources ◽  
Flow Through ◽  
Good Agreement

An experimental study was conducted on the heat transfer characteristics of flow through a porous channel with discrete heat sources on the upper wall. The temperatures along the heated channel wall were measured with different heat fluxes and the local Nusselt numbers were calculated at the different Reynolds numbers. The temperature distribution of the fluid inside the channel was also measured at several points. The experimental results were compared with that predicted by an analytical model using the Green’s integral over the discrete sources, and a good agreement between the two was obtained. The experimental results confirmed that the heat transfer would be more significant at leading edges of the strip heaters and at higher Reynolds numbers.

Solids Distribution in Sediment-Laden Open-Channel Flow: Experiment and Prediction

2020 ◽  
Author(s):  
Václav Matoušek ◽  
Jan Krupička ◽  
Tomáš Picek ◽  
Štěpán Zrostlik
Keyword(s):  
Channel Flow ◽  
Open Channel ◽  
Transport Model ◽  
Plane Surface ◽  
Open Channel Flow ◽  
Solid Particles ◽  
Experimental Results ◽  
Transport Layer ◽  
Experimental Investigations ◽  
Solids Concentration

Abstract Solid-liquid flow is studied in an open channel with a mobile bed at the condition of intense transport of solids. It is flow of high-concentrated mixture of coarse sediment and water over a plane surface of the bed eroded due to high bed shear. In the flow, solid particles are non-uniformly distributed across the flow depth. The flow develops a transport layer, adjacent to the the top of the bed, in which transported particles interact with each other. Results are presented of experimental investigations of the sediment-laden open-channel flow in a recirculating titling flume. The experiments included measurements (using ultrasonic techniques) of the distribution of solids velocity across the transport layer. The related distribution of solids concentration was deduced from the measured distribution of velocity and from other measured flow quantities. Since recently, a direct measurement of the solids distribution across the transport layer has been added to the experiments using a measuring technique svideo camera and a laser sheet. This work discusses results of combined measurements of the distributions of solids concentration and velocity in steady uniform turbulent flow for two lightweight solids fractions and various flow conditions (a broad range of the bed Shields parameter, discharge of solids, discharge of mixture, and the longitudinal slope of the bed). Furthermore, the camera-based measuring method and the deducing method for a determination of solids distribution are discussed and their results compared to show a good agreement in a majority of the test runs. The experimental results are compared with predictions of a recently developed bed-load transport model. Among other outputs, the model predicts the position of the top of the transport layer and the local velocity of sediment particles at this position. The presented model predictions agree well with experimental results based on the measured distibutions.

scholarly journals Enhanced Removal of Contaminants of Emerging Concern through Hydraulic Adjustments in Soil Aquifer Treatment

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2627
Author(s):  
Jana Sallwey ◽  
Anna Jurado ◽  
Felix Barquero ◽  
Jens Fahl
Keyword(s):  
Soil Column ◽  
Treated Wastewater ◽  
Management Technique ◽  
Soil Aquifer Treatment ◽  
Contaminants Of Emerging Concern ◽  
Removal Capacity ◽  
Soil Zone ◽  
Cycle Lengths ◽  
Wetting And Drying Cycle ◽  
Operational Modes

Water reclamation through the use of soil aquifer treatment (SAT) is a sustainable water management technique with high potential for application in many regions worldwide. However, the fate of contaminants of emerging concern (CECs) during the infiltration of treated wastewater during SAT is still a matter of research. This study investigates the removal capacity of 27 CECs during SAT by means of infiltration experiments into a 6 m soil column. Additionally, the influence of the hydraulic operation of SAT systems on the removal of CECs is investigated by changing the wetting and drying cycle lengths. Sixteen out of 27 CECs are efficiently removed during SAT under various operational modes, e.g., bezafibrate, diclofenac and valsartan. For six substances (4-methylbenzotriazole, amidotrizoic acid, benzotriazole, candesartan, hydrochlorothiazide and sulfamethoxazole), removal increased with longer drying times. Removal of amidotrizoic acid and benzotriazole increased by 85% when the drying cycle was changed from 100 to 444 min. For candesartan and hydrochlorothiazide, removal improved by 35%, and for 4-methylbenzotriazole and sulfamethoxazole, by 57% and 39%, respectively. Thus, enhanced aeration of the vadose soil zone through prolonged drying times can be a suitable technique to increase the removal of CECs during SAT.

Sign in / Sign up

Export Citation Format

Share Document