جستجوی مقالات مرتبط با کلیدواژه « soil column » در نشریات گروه « آب و خاک »

Crude oil is one of the most important sources of energy and its large scale production, transmission, consumption and disposal, making it one of the most important and common types of environmental pollution in the worldwide. In order to investigate the effects of phytoremediation and bioremediation on translocation of Total Petroleum Hydrocarbons (TPHs) in crude oil contaminated soil, a factorial experiment based on completely randomized design with three replications was conducted. Three rates of crude oil contamination; 0 (C0), 2 (C1) and 4% w/w (C2) and four remediation treatments; Lolium perenne (T1), Pseudomonas putida+Phanerochaete chrysosporium (T2), Lolium perenne+Pseudomonas putida+ Phanerochaete chrysosporium (T3) and control (T0) were applied. At the end of experiment, TPHs concentrations in different depths of soil column (5, 15, 25, 35 and 45 cm depths) were measured. The results showed that the different remediation treatments decreased the TPHs concentration in the root zone and T3 treatment decreased the concentration of TPHs both in C1 and C2 contamination rates by 34 and 59%, respectively. Oil compounds were also observed in the uncontaminated sub layers which indicated oil compounds transported from upper layer to lower layers. The lowest TPHs translocation to sub layers in the soil columns observed in T3 remediation treatment and the highest amount of TPHs translocation to sub layers observed in T2 remediation treatment. Generally, remediation treatments in oil contaminated soil degrade and decrease oil compounds specially in root zone but cannot prevent oil compounds movement and translocation to sub layers. Consequently, oil compounds may enter to groundwater.

Due to low efficiency of fertilizer use, nitrogen fertilizers result in environmental problems. Therefore, use of soil amendments such as zeolite becomes important. The aims of this study were to investigate the influence of size (mm and μm) and usage (20 and 60 grams per kilogram of soil) of natural zeolite of clinoptilolite (Cp) and surfactant-modified zeolite (SMZ) on soil nitrate and ammonium leaching and on wheat plant performance using soil columns and applying wastewater for irrigation at Greenhouse of Isfahan University of Technology in 2015-2016. The experiment was factorial with completely randomized design with three replications for each treatment. The results showed that these amendments simultaneously improved wheat plant growth and increased the amount of nitrogen uptake by plants. So that, the concentration of nitrogen of the grain and nitrogen harvested by the plant in Cp receptor columns were significantly (1.45 and 2.49%) higher than SMZ receptor columns. Also, with the increasing level of modifier usage, the amount of nitrate-nitrogen in the output decreased significantly (at 5% level). Still, the type of modifier had no significant effect on the amount of leached nitrogen.

The precise simulation of water and solute transfer in porous media is very important in soil and water studies. The purpose of this study was to measure and simulate water movement and solutes transfer of layered soils. In this study, the effect of soil bulk density changes and different soil layering on water and solute movement were measured and simulated with HYDRUS-1D model in 5 treatments and two replications. For this purpose, 10 columns of PVC with a height of 105 cm and an inner diameter of 31.5 cm, and three soil textures including loamy sand, sandy-clay loam and clay loam were used. The columns were irrigated with irrigation water and saline water with salinity of 0.67 and 4.46 ds/m, respectively. During the experiment, moisture content (using TDR moisture meter) and salinity (by saturated mud extraction method) were measured at depths of 10, 20, 30, 40 and 60 cm. The results of the study showed that the water movement in the soil is affected by the position of the layers with the least permeability and when the fine texture layer is placed on top, the time of water exit is the highest. Also, the results showed that in all columns the EC value was the highest in the upper layer and decreased from top to bottom regardless of the order of the arrangement of the layers. The survey of the nRMSE index indicates the high accuracy of the HYDRUS model in simulating the movement of water and solute in the layered soil. The lowest error in simulation was in homogeneous soil.

Powder sulfur is the most common used substance for improvement of calcareous soils particularly their pH while its efficiency in the soil is highly depend on its oxidation condition. The Objective of this research is to evaluate the efficiency of various amounts of sulfur to improve calcareous soils in presence of sulfur-oxidizer bacteria. Hence, 15 soil columns containing a calcareous soil including four sulfur treatments labeled S(0.125), S(0.250), S(0.375) and S(0.500) and a control treatment with lack of sulfur, each with three replications were manufactured and inoculated using Thiobacillus thioparus and then brought under leaching once a two weeks for six months. The results showed that the leakage of sulfate caused by sulfur oxidation was intensified for the temperatures above 25°C and reached a maximum in 30°C. Moreover, statistical analysis among sulfur treated columns approved presence of positive significant relationships between temperature and sulfate leakage (α= 0.01) from one hand, and negative significant relationships between temperature and pH (α= 0.01) on the other hand.

Evolution of fate, transfer, distribution and transportation of pollution waste liquid (leachate), is one of the most important problems in urban community and environment. On the other hand, soil has complex biological, physical and chemical properties; therefore, soil characteristics are considered as a natural filtering for much type of pollutants. For this purpose, an experiment in polyethylene columns in the five period over 20 days with in a completely randomized design to evaluate the rate of change of many important parameters such as acidity, salinity, total nitrogen and refined nickel in leachate soil columns, with different textures of soils (loam, clay loam and sandy loam), were implemented. The amount of leachate has been applied, considering the volume of leachate collected from the waste storage in the area of Agh Ghala landfill, with water content calculated based on the rate of 10-year area was considered and in intermittent flood conditions to the soil columns, were added. The average amount of pH value decreased with time and use more applied leachate anaerobic landfill in all three soil textures; however, this change was especially obvious in clay loam soil. The average quantity of EC in loam soil texture increased, but decreased in other soil textures, therefore, the downward movement in clay loam soils was more intensity than the other soils. The mean values of total nitrogen in the soil drainage in clay loam and loam reduced; however, in sandy loam soils increased. The average change regarding soil nickel values in clay loam decreased and in sandy loam and loam soil texture increased, however providing that there is no statistically significance. Although the application of latex on the amount of each of the desired parameters (such as nickel in loam and sandy loam, EC in loam and sandy loam soil and total nitrogen in sandy loam) increased in water drainage of leachate anaerobic landfill of Agh ghala, however, soil played an important role to improve the quality of leachate. The results confirmed it when the mean values of salinity and acidity in clay loam and sandy loam soils, nickel in sandy loam soil and total nitrogen in clay loam and loam decreased in output leachate anaerobic landfill than the input. Consequently, it seems the effect of clay loam soil in reducing parameter (Ec, pH, N and Ni) were higher and had more effective role in improve the quality of leachate.

Due to shortage of water, use of wastewater for irrigation is becoming more important. Also, using natural and non-toxic materials that increase fertilizer application efficiency and decrease nitrate leaching has gained increasing attention. The aims of this study were to investigate the effect of two sizes for particles, i.e. 1-1.68 mm and 53-63 μm, and two application rates (20 and 60 grams per kilogram of soil) of natural zeolite of clinoptilolite (Cp) and surfactant-modified zeolite (SMZ) on soil nitrate and ammonium leaching and wheat plant performance under irrigation by treated urban wastewater. The experiment was conducted in 2015-16 growing season. The experimental soils were placed in Polyethylene columns with 11 cm inner diameter and 65 cm height. The treatments were factorial combination of the variables in completely randomized design with three replications. The results showed that the total amount of released NO3-N from columns modified by SMZ and CP were 32% and 21% lower as compared to the control treatment. Also, these amendments improved wheat plant growth. There was no significant effect on nitrate leaching due to the particle size of the two soil amendments. CP and SMZ amendments are eco-friendly materials and results of the study showed that they were effective in controlling soil nitrate leaching and improving wheat plant growth.

The study of adsorption/desorption process for heavy metals in soil and the evaluation of how these are transferred or accumulated or what happens to them in layers of soil is an important issue, that has attracted the attention of many researchers. Ability of accumulated metal transfer in layers of soil, because of surface water infiltration, precipitation and even infiltration of municipal and industrial wastewater in soil on one hand, and desorption of metals from soil as solution and their transfer and percolation into groundwater, which causes groundwater pollution, on the other hand are among other reasons which add to the importance of these types of research. Flow of raw wastewater in layers of soil due to adsorption/desorption process leads to transport of metals in soil column. This research was carried out as field operations, the aim of which was to assess desorption process for metals Ni, Zn and Pb that exist in soil in Semnan industrial region due to raw wastewater infiltration that are released from soil.
After the region raw wastewater infiltration, changes of concentration of metals in soil layers were measured and a statistical assessment was carried out with data, then for infiltration of wastewater to be applied in soil a pit was excavated. Soil sampling from the lower layers of the infiltration pit was done and Samples depth was from 20 to 300 cm in different layers. Before infiltration of wastewater, samples from the lower depths of the infiltration pit was obtained and used for determining the initial concentration in the soil layers (pre-infiltration) and after infiltration of wastewater, amount of heavy metals concentrations in the same depths are considered as post-infiltration data. A statistical assessment was carried out for evaluating the effect of desorption process (a paired-samples T-test is used for comparison of means) for each metal in the total soil column. This assessment was conducted by using statistical package SPSS18.
The results indicate that, displacement in the center of mass happens from the top to the lower layers for the three metals. The statistical assessment indicated in this soil column, desorption process of Ni from soil to wastewater solution was effective, but for metals Zn and Pb was not. Transport ratio was calculated and for Ni, Zn and Pb were 136, 21 and 10, respectively. Dissolved concentration was calculated for Ni, Zn and Pb at the end of soil column were 4.07, 1.95 and 1.25 (ppm), respectively.
wastewater infiltration leads to transfer of all of metals towards more depths in soil column. Ni percolates into the groundwater much faster than other metals. The order obtained from metals affected by desorption process and amount of percolation into ground water was Ni>Zn>Pb.

Shortage of fresh water resources is a major concern all over the world. Availability of water for irrigation is one of the most important factors in arid and semiarid regions، and treated domestic wastewater becomes an important source. Even after treatment، wastewater may contain a great variety of microorganisms that are hazardous for humans and environment. Thereafter the potential transmission of pollution is a principle concern associated with the agricultural use of treated wastewater. Thereafter various irrigation techniques can be used associated with treated wastewater for agriculture. Accordingly، the present study was conducted on Fecal Coliform in the wastewater treatment in laboratory columns، having 30 cm diameter and 60 cm height irrigated using surface (DI) and subsurface drip irrigation systems (SDI). Samples of the effluent and soil solutions were collected from each column after each irrigation events. Results represented that crowd of bacteries increased in both columns. There were no significant difference between crowds of bacteries in the effluent columns of two irrigation systems. It was observed that contamination of 15 cm layer in SDI was lower than DI column.

Municipal wastewater is a potential source for water supplies. Soil organic matter can affect chemical quality of wastewater passing through the soil. This experiment was carried out to determine the effects of different levels of vermicompost on change of chemical properties of Cd enriched municipal wastewater of Yasouj station after continuous passing through the soil columns. A completely randomized design was used. Polyethylene columns (80 cm in length and 8 cm in diameter) filled with a clay loam soil during 8 periods of 10 days. Three levels of vermicompost comprising control (V1), 2% (V2) and 4 wt% (V3), were used respectively. At the end of each period, characteristics such as pH, electrical conductivity, phosphate, nitrate, total organic carbon and cadmium concentration were measured in drainage water. Results showed that the effect of both the time and vermicompost was significant on all measured factors. The average of all factors except for pH of the drainage water, showed a decreasing trend during the experiment. Maximum of EC, P, nitrate and total organic carbon were measured in V3 treatment. Vermicompost exhibited a significant effect on Cd concentration of drainage water. It seems that organic matter has a drastic effect on increasing mobility of Cd as well as on the other studied characteristics, hence soil organic matter content should be considered in the usage management of wastewater.

In many areas, the main source of surface and groundwater nitrogen pollution is agriculture and simulation models are useful tools in determining the contribution of nitrogen produced by agriculture in pollution of water resources. In this research, leaching of nitrate on a loam-silty to loam soil was measured and simulated using LEACHN model after calibration. The experimental design was complete randomize block. The planting media consist of 15 PVC lysimeters (soil column) with 40 cm diameter and 120 cm height. In these lysimeters, maize (Singel Cross 704) was planted. The nitrogen treatments were 0.0 (control), 150, 200, 250 and 300 kg N/ha as urea with three replications. The results were showed that at 120 cm soil depth and the end of growing season, the nitrate leachate in 150, 200, 250, and 300 kg ha-1 treatments were increased 132, 174, 134 and 182% relative to control, respectively. Comparison between the measured and simulated results showed that LEACHN overestimated the leached nitrate in drainage water with the relative error between 11.3% (300 kg ha-1 treatment) and 88.6% (control). The order of accuracy in simulations was obtained in 300, 200,150 and 250 kg ha-1, respectively. In general, the evaluation of LEACHN model showed that the accuracy of this model for simulation of nitrate leachate was relatively good.

Hydrocarbon pollutants with negative polluting effects cause changes on physical and chemical properties of soil and water and threaten their quality and human safety. The purpose of this research was to investigate the heavy and light soils behavior on transportation of gasoline and kerosene in a pilot scale and pulse condition. An equipment including glassy cylinders has been designed. The bulk density and porosity of the soils have been determined. Then, the amount of half and one pore volume, gasoline and kerosene were applied. Glassy cylinders were filled with soil homogeneously in the given depth and soils were saturated by water. In this stage, half and one pore volume of the kerosene and gasoline were applied on saturated soils. Eventually, output volume of gasoline, kerosene and water has been measured per time. Finally the breakthrough curve were drawn. The results showed that both pollutants went through the loamy sand soil by less retention and more velocity in comparison with silty clay one. In both soils, gasoline retention was more than kerosene and kerosene flowed out of the light and heavy soils by sharper gradient and less retardation and more velocity. This difference in the output rate of pollutants from light soil is more distinct than heavy one. The results of this investigation can be applied for pollution emission assessment in terms of pulse pollution and quality of soil reaction versus these pollutants.