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Researchers have recently focused their attention on emerging contaminants (ECs) in wastewater because they pose serious health and environmental risks. Because ECs are persistent in the environment and have the ability to disrupt the physiology of target receptors, they have been labeled as contaminants of recent environmental concern. For removing various ECs, a variety of treatment technologies have been developed, including biological, chemical, and physical methods. However, no single technology can currently effectively remove ECs, whereas hybrid systems have consistently proven to be more effective. Furthermore, the majority of existing technologies are energy and resource intensive, as well as expensive to maintain and operate. Furthermore, the majority of advanced treatment technologies that have been proposed have yet to be evaluated for large-scale feasibility. Some ECs, particularly pharmaceuticals and pesticides, were found to be significantly removed using a hybrid technique that included ozone/UV and granular activated carbon (GAC). Besides, the removal of effluent parameters (TDS, COD, TOC) was enhanced through the GAC surface oxidization as a catalyst with NaOH before the process and by ozone within the procedure as well. [ABSTRACT FROM AUTHOR]

As is well known to mineral processing scientists and engineers, fine and ultrafine particles are difficult to float mainly due to the low bubble-particle collision efficiencies. Though many efforts have been made to improve flotation performance of fine and ultrafine particles, there is still much more to be done. In this paper, the effects of nano-microbubbles (nanobubbles and microbubbles) on the flotation of fine (−38 + 14.36 μm) and ultrafine (−14.36 + 5 μm) chalcopyrite particles were investigated in a laboratory scale Denver flotation cell. Nano-microbubbles were generated using a specially-designed nano-microbubble generator based on the cavitation phenomenon in Venturi tubes. In order to better understand the mechanisms of nano-microbubble enhanced froth flotation of fine and ultrafine chalcopyrite particles, the nano-microbubble size distribution, stability and the effect of frother concentration on nanobubble size were also studied by a laser diffraction method. Comparative flotation tests were performed in the presence and absence of nano-microbubbles to evaluate their impact on the fine and ultrafine chalcopyrite particle flotation recovery. According to the results, the mean size of nano-microbubbles increased over time, and decreased with increase of frother concentration. The laboratory-scale flotation test results indicated that flotation recovery of chalcopyrite fine and ultrafine particles increased by approximately 16–21% in the presence of nano-microbubbles, depending on operating conditions of the process. The presence of nano-microbubbles increased the recovery of ultrafine particles (−14.36 + 5 μm) more than that of fine particles (−38 + 14.36 μm). Another major advantage is that the use of nano-microbubbles reduced the collector and frother consumptions by up to 75% and 50%, respectively. Keywords: Nanobubbles, Nano-microbubble, Bubble size distribution, Chalcopyrite, Froth flotation, Fine particles

Treatment of organic leachate is one the most controversial topics around the world which led this study to assess the efficiency of the combined oxidation and adsorption treatment (COAT) process in the treatment of forest polluting site (FPS) leachate by considering local experiments. The removal of effluent parameters (TDS, COD, BOD) was enhanced by oxidizing the GAC surface as a catalyst with NaOH before the process and by ozone within the procedure as well. comparison between COAT process and ozone-GAC was investigated based on variation in ozone dose, H2O2 and pH. Assessing the interacting effect of operating variables (i.e., ozone concentration, GAC density, reaction time and pH) provides valuable information for optimization. Response surface methodology (RSM) and for better prediction, another modeling tool, artificial neural networks (ANN), were employed. Moreover, the results of both software were compared and ANN showed a higher R2 of 0.908, 0.923, and 0.919 for TDS, COD, and BOD respectively in contrast with RSM (R2: TDS = 0.8538, COD = 0.9105, BOD = 0.8108). The optimized model's circumstances are the reaction time of 30.77 min, ozone dosage of 141.29 mg/l, pH of 7.2, and the GAC density of 1.29 gr/cm3 with the predicted removal percentage of 51.63%, 62.84%, and 56.13% for TDS, COD, and BOD respectively. Meanwhile, in the experimental situation among the various methods, the COAT process by the removal percentage of TDS = 59.47%, COD = 68.37%, and BOD = 67% showed proper efficiency. [ABSTRACT FROM AUTHOR]

One of the new methods used to remove the contaminants from effluent is the electrocoagulation method, which is sometimes combined with other methods to increase the removal efficiency of contaminants. To simultaneously remove nickel, cyanide, zinc, and copper, the combined method of photo-electrocoagulation was used along with an oxidizing agent, namely hydrogen peroxide (Hp). In addition, the effects of factors affecting the removal efficiency were studied, including pH, electrode arrangement, and current intensity. An electric current of 300 mA at a pH of 10 for 60 min, Fe-SS electrodes with a distance between them of 5 cm, and hydrogen peroxide at a rate of 4 mg/L were the ideal conditions needed to accomplish the photo-electrocoagulation-oxidation process. According to these study findings, when the combined method of photocatalyst-electrocoagulation-oxidation (Hp) was used, the highest removal efficiencies of nickel, cyanide, zinc, and copper were 85, 96, 94, and 98%, respectively. The results showed that using the combined photo-electrocoagulation-oxidation method increased the efficiency of simultaneous removal of pollutants by 10% compared to conventional electrocoagulation method. The reason for the increase in removal efficiency is the production of hydroxyl radicals simultaneously with the formation of coagulants produced by electrocoagulation process. [ABSTRACT FROM AUTHOR]

Concrete corrosion has a great economic impact on many worldwide projects especially in corrosive environments such as municipal sewer systems. Many different factors can cause corrosive attacks on concrete structures that can be categorized into two main groups, chemical sulfuric acid attack, and microbial corrosive process via producing biogenic sulfuric acid (BSA). The present work aimed on assessing the sulfur concrete durability in sewerage environment and investigating the effects of microbial corrosion on this type of concrete. In this study, two tests were conducted including sewer concrete pipe in situ, and experimental tests on cubic samples. For biological tests, this bacterium was chosen for performing laboratory tests since the presence probability and population of Thiobacillus thiooxidans microorganism in domestic sewer is higher than other species. Results showed that sulfur concrete is considerably resistant to severe acid attack, but is less resistant to microbial corrosion attack than chemical corrosion especially against sulfur oxidizing bacteria. This is completely different in Sewer environment, because the microbial attack is limited by some factors such as pH variety and other bacteria presence competition. [ABSTRACT FROM AUTHOR]

Cyanide, as one of the most toxic pollutants existing in the gold mine tailing dams, threatens human health and other species life. The main objective of this study was to simulate the oxidation of cyanide from mineral effluent of the Moteh Tailing Dam (Iran), as a method for removing cyanide. We employed PHREEQC software to model the oxidation of cyanide using calcium hypochlorite (Ca(OCl)2) and sodium hypochlorite (NaOCl). The results indicated that Ca(OCl)2 and NaOCl concentrations, as well as pH, influenced the oxidation of cyanide. The model was run in the constant temperature of 12°C and pH between 12 to 13. By rising Ca(OCl)2 concentration from 0.71 to 1.43 g/l and NaOCl concentration from 1.72 to 5.18 g/l, the removal rates of cyanide increased from 97.01% to 99.20% and 95.46% to 95.90%, respectively. The coefficient of determination (R2), index of agreement (IA), and Nash- Sutcliffe efficiency (E) were used to assess the predicted removal rate of cyanide in comparison with experimental observations, which demonstrated a suitable agreement: Ca(OCl)2 = 0.71 mg/l, R² = 0.97, IA = 0.91 and E = 0.73; Ca(OCl)2 = 0.85 mg/l, R² = 0.99, IA = 0.99, E = 0.96; Ca(OCl)2 = 1.43 mg/l, R² = 0.97, IA = 0.92, E = 0.79; NaOCl = 1.72 mg/l, R² = 0.97, IA = 0.92, E = 0.74; NaOCl = 3.45 mg/l, R² = 0.91, IA = 0.91, E = 0.71; NaOCl = 5.18 mg/l, R² = 0.96, IA = 0.91, E = 0.77. [ABSTRACT FROM AUTHOR]

One of the main challenges in the copper oxide processing industry is implementation of a flotation method to reduce operating costs. Sulphidising flotation is the most common used technique in which a sulphidisation agent is used to sulphidise the surface of the oxide minerals. In this research, the mentioned technique was used sequentially for the concentration of silicate-carbonate ore containing 3.1% Cu (malachite). The presence of 39% Cu in -38 μm size fraction (fine particles) of feed led to poor grades and recoveries in the initial tests. The addition of sodium sulfide and subsequent flotation at three sequential stages was identified as a successful operational initiative to solve this problem in the following tests. The dosages of 1500, 1567 and 100 g/Mg of sodium silicate, sodium sulfide and potassium amyl xanthate, respectively, the conditioning time of 5 min for sulphidisation and pH=9.72 were chosen as optimum operational conditions using central composite design (CCD) method of experiments design. The rougher concentrate with 9.28% grade and 81.15% recovery was obtained under these conditions. The grade of obtained concentrate was reached to 24% in the cleaner step. The total recovery of both steps was over 74%. [ABSTRACT FROM AUTHOR]

Feasibility of applying intelligent tools in prediction and optimization of photocatalytic degradation of beta-naphthol using the titanium dioxide (TiO2) nanoparticles were conducted in this study. Biphasic TiO2 nanoparticles were synthesized using the controlled hydrolysis of TiCl4, and their properties were studied using the X-ray diffraction and transmission electron microscopy methods. Therefore, factors affecting photocatalytic degradation of beta-naphthol including impurity concentration, catalyst content, acidity, and aeration rate were monitored and controlled. The laboratory data showed that degradation rate of beta-naphthol is a complicated nonlinear function of monitored variables. Two models including artificial network trained with particle swarm optimization (ANN-PSO) and adaptive neuro-fuzzy interference system trained with particle swarm optimization (ANFIS-PSO) were used for prediction of this system. The results showed presence of a significant relation between the real and predicted data of these 2 models. However, ANFIS-PSO can be more efficiently applied for prediction and optimization of photocatalytic behavior of TiO2 nanoparticles as for degradation of beta-naphthol as compared to ANN-PSO. As an advantage, ANFIS eliminates the problems of fuzzy logic, such as creation of membership functions, and local minima, which should be located in design of ANN, and through PSO algorithm, it could be a very powerful tool for simulating kinds of processes. [ABSTRACT FROM AUTHOR]

Antimony is one of the most toxic pollutants in industrial and mineral wastewaters threatening the life of humans and other creatures. We simulated the adsorption of antimony in the presence of nano-zero valent iron (nZVI) adsorbent, on kaolinite and in the presence of nZVI coated on kaolinite from mineral wastewater using VISUAL MINTEQ 3.1 software. Our aim was to determine the factors affecting the adsorption of antimony by applying simulation. The simulation was performed using an adsorption model of a diffuse layer model. The results of the simulation indicated that the nZVI concentration, initial concentrations of antimony and pH factor are effective on the adsorption of antimony. In the conducted stimulation, the optimum pH was 2-5 and the highest adsorption occurred in an acidic state. With increasing initial concentrations of antimony in the simulation, we concluded that nZVI had absorbed various concentrations above 90% and, by increasing the concentration of nZVI, antimony adsorption rate increased. The increased surface area of nZVI and the expansion of more interchangeable surfaces available for reaction with antimony ions causes more antimony ions to be adsorbed. In all cases, the coefficient of determination between the laboratory results and the model predictions that was obtained was more than 0.9. [ABSTRACT FROM AUTHOR]

Decolorization of wastewater of industries which consume dye is an environmental priority. Electrocoagulation and electroflotation methods are appropriate for treatment of these wastewaters. This study investigates the effect of four parameters, electrical conductivity, current density, initial dye concentration, and initial pH, on the performance of a simultaneous electrocoagulation/ electroflotation system for removal of Acid Red 14. The optimum values of these parameters were determined based on the amount of electrical energy and aluminum consumption and the best performance of coagulation and bubble generation. The optimum condition was revealed to be electrical conductivity= 1,600 μS/cm, current density = 60 mA/cm2, initial dye concentration = 185 mg/L and initial pH= 7. After less than 180 min of electrolysis, 90% dye removal was achieved with a specific energy consumption= 102 kWh/kg dyeremoved, anode dissolution= 2.09 kg Al/kg dyeremoved and sludge total suspended solids= 15,050 mg/L. Liquid chromatography-UV-mass spectroscopy analyses were conducted on samples of raw and treated wastewater. Results showed that intermediate compounds formed from the breaking of the dye molecules. The advantages of this method are a low material and energy consumption. The amount of produced sludge was low; consequently sludge disposal and management costs would be reduced. This method should be used cautiously for treatment of textile wastewater due to the formation of intermediate compounds. [ABSTRACT FROM AUTHOR]

In this paper geochemical modelling of mercury in tailing dam of Takab gold processing plant in North West. Iran has been investigated. For this aim, the mercury geochemical species and compositions were predicted, and possible neutralizations were determined through equilibrium geochemical model. The model is based on geochemical equilibrium, which uses the simultaneous solution of the non-linear mass action expressions and linear mass balance relationships to formulate and solve the multiple-component chemical equilibrium problems. In fact, it uses mass-law equations and formation constants for the set of species and material balance equations for each component to define the chemical equilibrium problem. In this study, the concentration of aqueous species in tailing dam was used as input in the model. The results of the model indicated that Hg2+ concentration increase in high pHs and temperatures is due to the reduction in the formation of mercury complex compositions. [ABSTRACT FROM AUTHOR]

Abstract: The chemical dissolution mechanism of natural orpiment polycrystals in a 1M NaOH solution has been investigated using a combination of spectroscopic, chromatographic and electrochemical methods. Two different types of electrodes were used for characterization of dissolution process by open-circuit potential (OCP) measurements, linear sweep (LSV) and cyclic voltammetry (CV). With one electrode, particles of yellow As2S3 were mechanically immobilized on the surface of the paraffin-impregnated graphite electrode (PIGE) and with the other electrode, As2S3 particles were homogeneously dispersed in a carbon paste electrode (CPE). In addition, leached solution species were characterized by (a) UV–vis spectroscopy, (b) ion chromatography and (c) CV using a platinum disc electrode. Arsenite and sulfide ions were detected during the initial solubilization step of orpiment followed by proposed thioarsenite and pentavalent arsenic species. Arsenate and thioarsenates species are minor components of the leaching solution. In addition, the oxidation of orpiment in alkaline media was investigated. The chemical properties of arsenic have an important role in the dissolution process and the chemical speciation over time. [Copyright &y& Elsevier]

In this work, the manganese ferrite was synthesized, and its effect on arsenite immobilization in soil was studied. The results of characterization using various experiments, including field emission scanning electron microscopy (FE-SEM) coupled with an energy-dispersive X-ray spectrometer, X-ray fluorescence (XRF), X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and Fourier transform infrared (FTIR), proved that nanoparticles were synthesized with an average diameter of 33.8 nm and surface area of 72.5 m2 g−1. The soil amendment process using the synthesized manganese ferrite led to a significant decrease in arsenite leachability/availability based on the Toxicity Characteristic Leaching Procedure (90.2%), Physiologically Based Extraction Test (88.2%), and plant bioavailability test (63.5%) results. According to the sequential extraction method, the association of arsenic in Fe-Mn oxide bounds increased to 70.2% and 82.3% using 1% and 10% manganese ferrite, respectively, indicating that arsenic availability and risk of release could be significantly reduced using the immobilization process. Furthermore, some parts of arsenite were converted to arsenate as a less toxic arsenic species, facilitating and increasing the effectiveness of the immobilization process. Moreover, based on the column tests results of arsenite elution, around 81.1% of water-soluble arsenite was converted into the associated form with the prepared manganese ferrite. In general, the present research demonstrated the high performance and effectiveness of the synthesized manganese ferrite in enhancing the arsenite immobilization process through reducing human bioaccessibility, plant bioavailability, risk of release, and leachability of arsenite. ga1 • Manganese ferrite greatly reduced leachability of As(III). • Manganese ferrite significantly reduced bioavailability of arsenite. • The promising result of arsenite immobilization was observed through column tests. • Some fractions of As(III) were oxidized to As(V) as a less toxic compounds. • Most of the loosely bounds of As converted to the stronger bound. [ABSTRACT FROM AUTHOR]

The co-precipitation method was used to synthesize nano-magnetic adsorbent MnFe 2 O 4 (nMFO), characterized through XRD, SEM, EDS, and BET techniques. The synthesized nMFO was used for hexavalent and trivalent chromium ions elimination from the aqueous phase. The optimum pH for the adsorption of Cr (VI) and Cr (III) was determined as 2 and 5, respectively. The chromium ions adsorption behavior was well interpreted through the pseudo-second order kinetics model. Furthermore, isotherm studies were conducted, and the obtained results indicated that Langmuir isotherm model could well justify the chromium ions adsorption process. Quick removal (less than 10 min) of both chromium ions and high removal efficiency were occurred using nMFO. The utmost adsorption capacity of trivalent and hexavalent chromium ions were determined as 39.6 and 34.84 mg g−1, respectively. Thermodynamic studies on chromium adsorption revealed positive value for ΔH and negative value for ΔG, representing that chromium ions adsorption was an endothermic and spontaneous process. The multilinearity in the graphs of chromium ions adsorption was observed using intra-particle diffusion model. In this regard, the external mass transfer of chromium ions on synthesized nanoparticles was the important and controlling step in the adsorption process. Image 1 • The high adsorption efficiency of Cr(VI) and Cr(III) was obtained using nMFO. • Rapid removal (less than 10 min) of both chromium ions was occurred using nMFO. • Electrostatic phenomena was the probable mechanism of Cr(VI) elimination. • Cation exchange was the main mechanism for the elimination of Cr(III). • The external mass transfer of chromium ions was the controlling step of the adsorption. Main finding : Rapid removal (less than 10 min) of both chromium ions was occurred using nMFO. Moreover, Electrostatic phenomena and cation exchange were the main mechanism for the elimination of Cr(VI) and Cr(III), respectively. [ABSTRACT FROM AUTHOR]

Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering possibility, it is advantageous to remove impurities and increase the pyrite content of mine tailings prior to the roasting procedure. In this case, hydrofluoric acid that has no influence on pyrite can be used to leach most inorganic minerals, including aluminosilicates. Therefore, this study investigated and compared the influence of the roasting process with and without hydrofluoric acid leaching pretreatment on mineralogical phase transformation of pyrite and magnetic properties of thermally generated minerals. Several tests and analyses were performed to study mineralogical phase transformation, morphology, elemental composition, surface characterization, and magnetic properties. Results of this study indicated that without acid leaching pretreatment, pyrite was mainly transformed to hematite. However, via acid leaching, fluorine, as a more electronegative element over oxygen, entered the compound and neglected the role of oxygen in thermal oxidation, instead reducing sulfur content of pyrite to only form pyrrhotite. [ABSTRACT FROM AUTHOR]

Remediation of soils contaminated with hydrocarbon materials is of particular importance due to their association with food chain. One of the remediation methods, which has been taken into account in recent years by researchers, is the electrokinetic technique. In this study, the electrokinetic method was used in combination with the Fenton technique to remove phenanthrene from clay soil. Oxidizing agent and catalyst used in the Fenton technique greatly influenced the efficiency of the remediation process. To investigate the effect of these two factors on the remediation process, it was made use of three different types of electrodes as catalyst, including graphite, iron, and copper, as well as hydrogen peroxide and sodium persulfate with different concentrations as oxidizing agent. During the 9 experiments designed, factors affecting removal efficiency, such as remediation time, electric current intensity, electroosmotic flow rate, and pH of the cathode and anode reservoirs were also investigated. Overall, the use of the electrokinetic-Fenton method with 15% hydrogen peroxide and copper electrode exhibited a 100% increase in the process efficiency over the same time period required to perform the conventional electrokinetic method and removed 93% of the soil phenanthrene, these findings indicated that combining the Fenton technique with the electrokinetic method enhanced the efficiency of this method in removing organic pollutants from the soil. Also, the use of sodium persulfate as an oxidizing agent in the electrokinetic method increased the removal efficiency by more than 95% over the half time period required to perform the conventional electrokinetic method. Image 1 • The combination of EK with Fenton method has increased the efficiency of phenanthrene removal. • The optimal amount of oxidizing agent in order to remove phenanthrene from soil is 15%. • The use of Iron and Copper electrodes increased the efficiency of phenanthrene removal from the soil. • The use of sodium persulfate increased the remediation efficiency and reduced the remediation time. [ABSTRACT FROM AUTHOR]

This study was aimed to investigate the effectiveness of compounds containing iron and manganese to reduce the mobility of arsenic and its effective adsorption and optimize the arsenic adsorption process by CCD. In this study, MnFe 2 O 4 nanoparticles (MFO-n) were synthesized using the co-precipitation method to remove arsenic and reduce its toxicity in solution. Several tests including Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray fluorescence (XRF), and Brunauer-Emmett-Teller (BET) tests were used to characterize the synthesized MFO-n. To model and optimize the As adsorption process using the response surface methodology, four independent variables affecting the efficiency of arsenic adsorption were investigated. These variables including pH (3 to 11), concentration of arsenic in solution (1000 to 4000 µg/L), concentration of nanoparticles (1 to 5 g/L), and time (15 to 195 min) were investigated. The central composite design (CCD) approach was used to design the experiments and optimize the model parameters. The variance analysis indicated that the prediction of As adsorption from solution by the synthesized nanoadsorbent using the CCD model was well performed (p < 0.0001) with high accuracy (R 2  = 0.97). The results further indicated that the optimum quantity of pH, concentration of nanoparticles, time, and initial concentration of As are 5, 2 g/L, 60 min, and 3250 µg/L, respectively. The highest As elimination from the solution was estimated to be 94.77%. Our results further indicated that MFO-n had high efficiency in eliminating both toxic arsenic species from the solution., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The co-precipitation method was used to synthesize nano-magnetic adsorbent MnFe 2 O 4 (nMFO), characterized through XRD, SEM, EDS, and BET techniques. The synthesized nMFO was used for hexavalent and trivalent chromium ions elimination from the aqueous phase. The optimum pH for the adsorption of Cr (VI) and Cr (III) was determined as 2 and 5, respectively. The chromium ions adsorption behavior was well interpreted through the pseudo-second order kinetics model. Furthermore, isotherm studies were conducted, and the obtained results indicated that Langmuir isotherm model could well justify the chromium ions adsorption process. Quick removal (less than 10 min) of both chromium ions and high removal efficiency were occurred using nMFO. The utmost adsorption capacity of trivalent and hexavalent chromium ions were determined as 39.6 and 34.84 mg g -1 , respectively. Thermodynamic studies on chromium adsorption revealed positive value for ΔH and negative value for ΔG, representing that chromium ions adsorption was an endothermic and spontaneous process. The multilinearity in the graphs of chromium ions adsorption was observed using intra-particle diffusion model. In this regard, the external mass transfer of chromium ions on synthesized nanoparticles was the important and controlling step in the adsorption process., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, surface soils of the Bama Pb-Zn mine-impacted area were sampled for an area surrounding the mineral processing plant. After collecting 65 samples and analyzing them for initial Cu, Pb, Zn, and Cd metal contents, the area was zonated based on the concentration distribution using ordinary kriging in R. A single homogenous sample was prepared by mixing equal weights of each sample as being representative of the whole impacted area (S T ). Next, a synthetic model soil (S M ) was prepared according to the mean S T texture (S M ), divided into two portions, where one portion was amended with a biochar composite (10% w/w) (S MA ), both portions were artificially contaminated with Cu, Pb, Zn, and Cd (S MAC and S MC ). The mixed soil S T , and the model soils S MC and S MAC , were subjected to soil sequential extraction procedure to determine the variations in fractionation of heavy metals. Results showed that the fractionation in the unamended model soil (S MC ) was very close to the original real soil (S T ). Moreover, in both amended and unamended soils, Cd and Pb had the highest and the lowest mobility, respectively. Zn and Cu showed intermediate mobilities. The performance of the amendment was evaluated using a 150-day column leaching test taking leachate samples at designated time intervals, and Cu, Pb, Zn, and Cd concentrations were analyzed. Results of column leaching were in good agreement with the soil fractionation as Cd and Pb showed the highest and the lowest mobilities, respectively. Leaching through the soil column was also simulated by HP1 model. Results of simulation found in acceptable proximity to the experimental data despite remarkable differences due to limitations in defining soil to the simulation system.