Search results for: contaminated soil

Authors: Johnson Rotimi Oluremi, A. Adedayo Adegbola, A. Samson Adediran, O. Solomon Oladapo

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Spent engine oil contains heavy metals and polycyclic aromatic hydrocarbons which contribute to chronic health hazards, poor soil aeration, immobilisation of nutrients and lowering of pH in soil. It affects geotechnical properties of lateritic soil thereby constituting geotechnical and foundation problems. This study is therefore based on the stabilization of spent engine oil (SEO) contaminated lateritic soil using cement kiln dust (CKD) as a mean of restoring it to its pristine state. Geotechnical tests which include sieve analysis, atterberg limit, compaction, California bearing ratio and unconfined compressive strength tests were carried out on the natural, SEO contaminated and CKD stabilized SEO contaminated lateritic soil samples. The natural soil classified as A-2-7 (2) by AASHTO classification and GC according to the Unified Soil Classification System changed to A-4 non-plastic soil due to SEO contaminated even under the influence of CKD it remained unchanged. However, the maximum dry density (MDD) of the SEO contaminated soil increased while the optimum moisture content (OMC) behaved vice versa with the increase in the percentages of CKD. Similarly, the bearing strength of the stabilized SEO contaminated soil measured by California Bearing Ratio (CBR) increased with percentage increment in CKD. In conclusion, spent engine oil has a detrimental effect on the geotechnical properties of the lateritic soil sample but which can be remediated using 10% CKD as a stand alone admixture in stabilizing spent engine oil contaminated soil.

Keywords: spent engine oil, lateritic soil, cement kiln dust, stabilization, compaction, unconfined compressive strength

Procedia PDF Downloads 390

Authors: M. N. Alo, U. C. C. Egbule, J. O. Orji, C. J. Aneke

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Microbiological analysis of soil from Onu-Ebonyi Izzi local government area of Ebonyi State, Nigeria contaminated with inorganic fertilizer was carried out with a view to determine the effect of the fertilizer on the microbial flora of the soil. soil samples were analyzed for microbial burden. the result showed that the following organisms were isolated with their frequency of their occurrence as follows:pseudomonas species (33.3%) and aspergillus species (54.4%) had the highest frequncy of occurence in the whole sample of batches, while streptococcus species had 6.0% and Geotrichum species (5.3%) had the least and other predominant microorganism isolated: bacillus species,staphylococcus species and vibrio species, Escherichia species, rhzizopus species, mucor species and fusaruim species. From the result, it could be concluded that the soil was contaminated and this could affect adversely the fertility of the soil .

Keywords: soil, bacteria, fungi, inorganic fertilizer, Onu- Ebonyi

Procedia PDF Downloads 512

Authors: M. Grifoni, G. Petruzzelli, M. Barbafieri, I. Rosellini, B. Pezzarossa, F. Pedron

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Evapotranspiration (ET) covers are an alternative cover system that utilizes water balance approach to maximize the ET process to reduce the contaminants leaching through the soil profile. Microcosm tests allow to identify in a short time the most suitable plant species to be used as alternative covers, their survival capacity, and simultaneously the transpiration and evaporation rate of the cover in a specific contaminated soil. This work shows the soil characterization and ET results of microcosm tests carried out on two contaminated soils by using Triticum durum and Helianthus annuus species. The data indicated that transpiration was higher than evaporation, supporting the use of plants as alternative cover at this contaminated site.

Keywords: contaminated sites, evapotranspiration cover, evapotranspiration, microcosm experiments

Procedia PDF Downloads 291

Authors: Z. H. Shi, T. J. Dou, H. Zhang, H. X. Huang, N. Zeng

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The contamination of significant quantities of soils and sediments with uranium and other actinide elements as a result of nuclear activity poses many environmental risks. The electrokinetic process is one of the most promising remediation techniques for sludge, sediment, and saturated or unsaturated soils contaminated with heavy metals and radionuclides. However, secondary waste is a major concern for soil contaminated with nuclides. To minimize the generation of secondary wastes, this study used the anion and cation exchange membranes to improve the performance of the experimental apparatus. Remediation experiments of uranium-contaminated soil were performed with different agents. The results show that using acetic acid and EDTA as chelating agents clearly enhances the migration ability of the uranium. The ion exchange membranes (IEMs) used in the experiments not only reduce secondary wastes, but also, keep the soil pH stable.

Keywords: electrokinetic remediation, ion exchange membranes, soil, uranium

Procedia PDF Downloads 352

Authors: Tawar Mahmoodzadeh

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Today soil contamination is an unavoidable issue; Irrespective of environmental impact, which happens during the soil contaminating and remediating process, the influence of this phenomenon on soil has not been searched thoroughly. In this study, unconfined compression and compaction tests were done on samples, contaminated and treated soil after 50 days of bio-treatment. The results show that rising in the amount of oil, cause decreased optimum water content and maximum dry density and increased strength. However, almost 65% of this contamination terminated by using a Bioremer as a bioremediation agent.

Keywords: oil contamination soil, shear strength, compaction, bioremediation

Procedia PDF Downloads 155

Authors: Celia Marilia Martins, Sonia I. V. Guilundo, Iris M. Victorino, Antonio O. Quilambo

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In Mozambique rapid industrialization (mining, aluminium and cement activities) and urbanization processes has led to the incorporation of heavy metals on soil, thus degrading not only the quality of the environment, but also affecting plants, animals and human healthy. Several methods have been used to remediate contaminated soils, but most of them are costly and difficult to get optimum results. Currently, phytoremediation is an effective and affordable technological solution used to extract or remove inactive metals from contaminated soil. Phytoremediation is the use of plants to clean up a contamination from soils, sediments, and water. This technology is environmental friendly and potentially cost effective. The present investigation summarised the potential of edible vegetable to grow under the high level of heavy metals such as lead and zinc. The plants used in these studies include Tomatoes, lettuce and Soya beans. The studies have shown that edible plants can be grown under the high level of heavy metals on the soil. Further investigations are identifying mechanisms used by plants to ensure a safe and sustainable use for remediation of contaminated soils by heavy metals.

Keywords: contaminated soil, edible plants, heavy metals, phytoremediation

Procedia PDF Downloads 377

Authors: Abdelouahab Diafat, Meribai Abdelmalek, Ahmed Bahloul

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phytoremediation is the use of plants to remove or degrade organic or inorganic contaminants from soil and water this work aims to study the potential effect of malva sylvestris for the phytoremediation of soils contaminated by Zn. plants were grown in pots containing soil artificially contaminated with Zn at concentrations of 100, 200, and 300 mg/kg. the results obtained show that the Zn concentrations used have a negative effect on the growth of this plant the search for the metal carried out by the technique of atomic absorption spectrometry shows that this plant accumulates a small quantity of this metal. it can be concluded that the malva sylvestris plant tolerates Zn contaminated soils but it is not considered as a zinc hyperaccumulator plant

Keywords: phytoremidiation, Zn-contaminated soils, Malva Sylvestris, phytoextraction

Procedia PDF Downloads 89

Authors: M. A. Stoian, D. M. Cocarta, A. Badea

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The main sources of soil pollution due to petroleum contaminants are industrial processes involve crude oil. Soil polluted with crude oil is toxic for plants, animals, and humans. Human exposure to the contaminated soil occurs through different exposure pathways: Soil ingestion, diet, inhalation, and dermal contact. The present study research is focused on soil contamination with heavy metals as a consequence of soil pollution with petroleum products. Human exposure pathways considered are: Accidentally ingestion of contaminated soil and dermal contact. The purpose of the paper is to identify the human health risk (carcinogenic risk) from soil contaminated with heavy metals. The human exposure and risk were evaluated for five contaminants of concern of the eleven which were identified in soil. Two soil samples were collected from a bioremediation platform from Muntenia Region of Romania. The soil deposited on the bioremediation platform was contaminated through extraction and oil processing. For the research work, two average soil samples from two different plots were analyzed: The first one was slightly contaminated with petroleum products (Total Petroleum Hydrocarbons (TPH) in soil was 1420 mg/kg_d.w.), while the second one was highly contaminated (TPH in soil was 24306 mg/kg_d.w.). In order to evaluate risks posed by heavy metals due soil pollution with petroleum products, five metals known as carcinogenic were investigated: Arsenic (As), Cadmium (Cd), Chromium^VI (Cr^VI), Nickel (Ni), and Lead (Pb). Results of the chemical analysis performed on samples collected from the contaminated soil evidence soil contamination with heavy metals as following: As in Site 1 = 6.96 mg/kg_d.w; As in Site 2 = 11.62 mg/kg_d.w, Cd in Site 1 = 0.9 mg/kg_d.w; Cd in Site 2 = 1 mg/kg_d.w; Cr^VI was 0.1 mg/kg_d.w for both sites; Ni in Site 1 = 37.00 mg/kg_d.w; Ni in Site 2 = 42.46 mg/kg_d.w; Pb in Site 1 = 34.67 mg/kg_d.w; Pb in Site 2 = 120.44 mg/kg_d.w. The concentrations for these metals exceed the normal values established in the Romanian regulation, but are smaller than the alert level for a less sensitive use of soil (industrial). Although, the concentrations do not exceed the thresholds, the next step was to assess the human health risk posed by soil contamination with these heavy metals. Results for risk were compared with the acceptable one (10^-6, according to World Human Organization). As, expected, the highest risk was identified for the soil with a higher degree of contamination: Individual Risk (IR) was 1.11×10^-5 compared with 8.61×10^-6. 

Keywords: carcinogenic risk, heavy metals, human health risk assessment, soil pollution

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Authors: Juan Francisco Morales Arteaga, Simon Gluhar, Anela Kaurin, Domen Lestan

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Contaminated soils are recognized as one of the most pressing global environmental problems. As is one of the most hazardous elements: chronic exposure to arsenic has devastating effects on health, cardiovascular diseases, cancer, and eventually death. Pb, Zn and Cd are very highly toxic metals that affect almost every organ in the body. With this in mind, new technologies for soil remediation processes are urgently needed. Calcareous artificially contaminated soil containing 231 mg kg-1 As and historically contaminated with Pb, Zn and Cd was washed with a 1:1.5 solid-liquid ratio of 90 mM EDTA, 100 mM oxalic acid, and 50 mM sodium dithionite to remove 59, 75, 29, and 53% of As, Pb, Zn, and Cd, respectively. To reduce emissions of residual EDTA and chelated metals from the remediated soil, zero valent iron (ZVI) was added (1% w/w) to the slurry of the washed soil immediately prior to rinsing. Experimental controls were conducted without the addition of ZVI after remediation. The use of ZVI reduced metal leachability and minimized toxic emissions 21 days after remediation. After this time, NH4NO3 extraction was performed to determine the mobility of toxic elements in the soil. In addition, Unified Human BioaccessibilityMethod (UBM) was performed to quantify the bioaccessibility levels of metals in stimulated human gastric and gastrointestinal phases.

Keywords: soil remediation, soil science, soil washing, toxic metals removal

Procedia PDF Downloads 175

Authors: Cora Bulmău

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Soil polluted with hydrocarbons spills is a major global concern today. As a response to this issue, our experimental study tries to put in evidence the option to choose for one environmentally friendly method: use of the biochar, despite to a classical procedure; incineration of contaminated soil. Biochar represents the solid product obtained through the pyrolysis of biomass, its additional use being as an additive intended to improve the quality of the soil. The positive effect of biochar addition to soil is represented by its capacity to adsorb and contain petroleum products within its pores. Taking into consideration the capacity of the biochar to interact with organic contaminants, the purpose of the present study was to experimentally establish the effects of the addition of wooden biomass-derived biochar on a soil contaminated with oil. So, the contaminated soil was amended with biochar (10%) produced by pyrolysis in different operational conditions of the thermochemical process. After 25 days, the concentration of petroleum hydrocarbons from soil treated with biochar was measured. An analytical method as Soxhlet extraction was adopted to estimate the concentrations of total petroleum products (TPH) in the soil samples: This technique was applied to contaminated soil, also to soils remediated by incineration/adding biochar. The treatment of soil using biochar obtained from pyrolysis of the Birchwood led to a considerable decrease in the concentrations of petroleum products. The incineration treatments conducted under experimental stage to clean up the same soil, contaminated with petroleum products, involved specific parameters: temperature of about 600°C, 800°C and 1000°C and treatment time 30 and 60 minutes. The experimental results revealed that the method using biochar has registered values of efficiency up to those of all incineration processes applied for the shortest time.

Keywords: biochar, biomass, remediaton, soil, TPH

Procedia PDF Downloads 237

Authors: Sarra Arbaoui, Taoufik Bettaieb

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Contaminated soils and problems related to them have increasingly become a matter of concern. The most common the contaminants generated by industrial urban emissions and agricultural practices are trace metals). Remediation of trace metals which pollute soils can be carried out using physico-chemical processes. Nevertheless, these techniques damage the soil’s biological activity and require expensive equipment. Phytoremediation is a relatively low-cost technology based on the use of selected plants to remove, degrades or contains pollutants. The potential of kenaf for phytoremediation on Cd-contaminated soil was investigated. kenaf plants have been grown in pots containing different concentrations of cadmium. The observations made were for biomass production and cadmium content in different organs determinate by atomic emission spectrometry. Cadmium transfer from a contaminated soil to plants and into plant tissues are discussed in terms of the Bioconcentration Factor (BCF) and the Transfer Factor (TF). Results showed that Cd was found in kenaf plants at different levels. Tolerance and accumulation potential and biomass productivity indicated that kenaf could be used in phytoremediation.

Keywords: kenaf, cadmium, phytoremediation, contaminated soil

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Authors: Waddah S. Abdullah, Saleh M. Al-Sarem

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Electrokinetic remediation of contaminated soils has undoubtedly proven to be one of the most efficient techniques used to clean up soils contaminated with polar contaminants (such as heavy metals) and nonpolar organic contaminants. It can efficiently be used to clean up low permeability mud, wastewater, electroplating wastes, sludge, and marine dredging. EK processes have proved to be superior to other conventional methods, such as the pump and treat, and soil washing, since these methods are ineffective in such cases. This paper describes the use of electrokinetic remediation to clean up soils contaminated with nickel. Open cells, as well as advanced cylindrical cells, were used to perform electrokinetic experiments. Azraq green clay (low permeability soil, taken from the east part of Jordan) was used for the experiments. The clayey soil was spiked with 500 ppm of nickel. The EK experiments were conducted under direct current of 80 mA and 50 mA. Chelating agents (NaEDTA), disodium ethylene diamine-tetra-ascetic acid was used to enhance the electroremediation processes. The effect of carbonates presence in soils was, also, investigated by use of sodium carbonate. pH changes in the anode and the cathode compartments were controlled by using buffer solutions. The results showed that the average removal efficiency was 64%, for the Nickel spiked saturated clayey soil.Experiment results have shown that carbonates retarded the remediation process of nickel contaminated soils. Na-EDTA effectively enhanced the decontamination process, with removal efficiency increased from 64% without using the NaEDTA to over 90% after using Na-EDTA.

Keywords: buffer solution, contaminated soils, EDTA enhancement, electrokinetic processes, Nickel contaminated soil, soil remediation

Procedia PDF Downloads 246

Authors: Ghazal Horiat, Alireza Hajiani Bushehrian

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leakage of contamination from fuel or oil reservoirs can alter the geotechnical properties of the soil under their foundation and finally affect their performance in their service life. This article investigates the behavior of shallow foundations on the soil contaminated with diesel and kerosene using the Plaxis Tunnel3D V1.2 software. The information required for the numerical modeling in the paper was obtained from a similar experimental study. The present study seeks to compare the behavior of square foundations on sandy soil without contamination and the soil contaminated with different percentages of diesel and crude oil. The study was conducted on a small square foundation. The depth of the contamination was assumed constant, and the soil was evaluated with four different percentages of both contaminants. The results of analyses were plotted and assessed in the form of load-displacement curves for the foundation. The results indicate reduced bearing capacity of the foundation with the rise in the contamination percentage.

Keywords: bearing capacity, contaminated soils, shallow foundations, 3D numerical analysis

Procedia PDF Downloads 144

Authors: A. Özyer, N. G. Turan, Y. Ardalı

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The environmental fate of organic contaminants in soils is influenced significantly by the pH, texture of soil, water content and also presence of organic matter. In this study, biodegradation of endosulfan isomers was studied in two different soils (Soil A and Soil B) that have contrasting properties in terms of their texture, pH, organic content, etc. Two Nocardia sp., which were isolated from soil, were used for degradation of endosulfan. Soils were contaminated with commercial endosulfan. Six sets were maintained from two different soils, contaminated with different endosulfan concentrations for degradation experiments. Inoculated and uninoculated mineral media with Nocardia isolates were added to the soils and mixed. Soils were incubated at a certain temperature (30 °C) during ten weeks. Residue endosulfan and its metabolites’ concentrations were determined weekly during the incubation period. The changes of the soil microorganisms were investigated weekly.

Keywords: endosulfan, biodegradation, Nocardia sp. soil, organochlorine pesticide

Procedia PDF Downloads 385

Authors: Gavin Hutama Farandiarta, Hegi Adi Prabowo, Istiara Rizqillah Hanifah, Millati Hanifah Saprudin, Raden Iqrafia Ashna

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The increase of the petroleum’s consumption rate encourages industries to optimize and increase the activity in processing crude oil into petroleum. However, although the result gives a lot of benefits to humans worldwide, it also gives negative impact to the environment. One of the negative impacts of processing crude oil is the soil will be contaminated by petroleum sewage sludge. This petroleum sewage sludge, contains hydrocarbon compound and it can be calculated by Total Petroleum Hydrocarbon (TPH).Petroleum sludge waste is accounted as hazardous and toxic. The soil contamination caused by the petroleum sludge is very hard to get rid of. However, there is a way to manage the soil that is contaminated by petroleum sludge, which is by using heat (thermal desorption) in the process of remediation. There are several factors that affect the success rate of the remediation with the help of heat which are temperature, time, and air pressure in the desorption column. The remediation process using the help of heat is an alternative in soil recovery from the petroleum pollution which highly effective, cheap, and environmentally friendly that produces uncontaminated soil and the petroleum that can be used again.

Keywords: petroleum sewage sludge, remediation soil, thermal desorption, total petroleum hydrocarbon (TPH)

Procedia PDF Downloads 249

Authors: Shinen B., Bavor J., Dorjkhand B., Suvd B., Maitsetseg B.

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A number of remediation techniques are available for the treatment of soils and sediments contaminated by heavy metals. However, some of these techniques are expensive and environmentally disruptive. Nanomaterials are used in the environment as environmental catalysts to convert toxic substances from water, soil, and sediment into environmentally benign compounds. This study was carried out to scrutinize the feasibility of vivianite nanoparticles for remediation of soils contaminated with heavy metals. Column experiments were performed in the laboratory to examine nanoparticle sequestration of metal in soil amended with vivianite nanoparticle suspension. The effect of environmental parameters such as temperature, pH and redox potential on metal leachability and bioavailability of soil amended with nanoparticle suspension was examined and compared with non-amended soils. The vivianite was effective in reducing the leachability of metals in soils. It is suggested that vivianite nanoparticles could be applied for the remediation of contaminated sites polluted by heavy metals due to mining activities, particularly in Mongolia, where mining industries have been developing rapidly in the last decade.

Keywords: bioavailability, heavy metals, nanoparticles, remediation

Procedia PDF Downloads 192

Authors: Ali Gharaee, Mohammad Reza Khosravi Nikou, Bagher Anvaripour, Ali Asghar Mahjoobi

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Soil contamination by petroleum hydrocarbon (PHC) is a major concern facing the oil and gas industry. Particularly, condensate liquids have been found to contaminate soil at gas production sites. The remediation of PHCs is a difficult challenge due to the complex interaction between contaminant and soil. A study has been conducted to enhance degradation of PHCs by Fenton oxidation and using Nanoscale Zero-Valent Iron as catalyst. The various operating conditions such as initial H2O2 concentration, nZVI dosage, reaction time, and initial contamination dose were investigated. Central composite design was employed to optimize and analyze the effect of operational parameters on the PHC removal efficiency. It was found that optimal molar ratio of H2O2/Fe0 was 58 with maximum TPH removal of 84% and 3hr reaction time and initial contaminant concentration was 15g oil /kg soil. Based on the results, combination of Nanoscale ZVI and Fenton has proved to be a promising remedy for contaminated soil.

Keywords: oil contaminated Soil, fenton oxidation, zero valent iron nano-particles

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Authors: R. O. Anyasi, H. I. Atagana

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In this study, phytoextraction ability of a weed on Aroclor 1254 was studied under greenhouse conditions. Chromolaena odorata plants were transplanted into soil containing 100, 200, and 500 ppm of Aroclor in 1L pots. The experiments were watered daily at 70 % moisture field capacity. Parameters such as fully expanded leaves per plant, shoot length, leaf chlorophyll content as well as root length at harvest were measured. PCB was not phytotoxic to C. odorata growth but plants in the 500 ppm treatment only showed diminished growth at the sixth week. Percentage increases in height of plant were 45.9, 39.4 and 40.0 for 100, 200 and 500 ppm treatments respectively. Such decreases were observed in the leaf numbers, root length and leaf chlorophyll concentration. The control sample showed 48.3 % increase in plant height which was not significant from the treated samples, an indication that C. odorata could survive such PCB concentration and could be used to remediate contaminated soil. Mean total PCB absorbed by C. odorata plant was between 6.40 and 64.60 ppm per kilogram of soil, leading to percentage PCB absorption of 0.03 and 17.03 % per kilogram of contaminated soil. PCBs were found mostly in the root tissues of the plants, and the Bioaccumulation factor were between 0.006-0.38. Total PCB absorbed by the plant increases as the concentration of the compound is increased. With these high BAF ensured, C. odorata could serve as a promising candidate plant in phytoextraction of PCB from a PCB-contaminated soil.

Keywords: phytoremediation, bioremediation, soil restoration, polychlorinated biphenyls (PCB), biological treatment, aroclor

Procedia PDF Downloads 382

Authors: Ahmed Mohamed Nasr, Waseim Ragab Azzam, Nada Osama Ramadan

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Contaminated soil can weaken the stability of buildings and infrastructure, posing serious risks to their structural integrity. Therefore, this study aims to understand how oil contamination affects the torsion behavior of model steel piles at different soil densities. This research is crucial for evaluating the structural integrity and stability of piles in oil-contaminated environments. Clean sand samples and heavy motor oil were mixed in amounts ranging from 0 to 6% of the soil's dry weight. The mixture was thoroughly mixed to ensure uniform distribution of the oil throughout the sandy soil for simulating the field conditions. In these investigations, the relative densities (Dr), pile slenderness ratio (Lp/Dp), oil content (O.C%), and contaminated sand layer thickness (LC) were all different. Also, the paper presents an analysis of piles that are loaded both vertically and torsionally. The findings demonstrated that the pre-applied torsion load led to a decrease in the vertical bearing ability of the pile. Also, at Dr = 80%, the ultimate vertical load under combined load at constant torsional load T = (1/3Tu, 2/3Tu, and Tu) in the cases of (Lc/Lp) = 0.5 and (Lp/Dp) =13.3 was found to be reduced by (1.48, 2.78, and 4.15%) less than piles under independent vertical load, respectively so it is crucial to consider the torsion load during pile design.

Keywords: torsion-vertical load, oil-contaminated sand, twist angle, steel pile

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Authors: Chinumani Choudhury

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Heavy metal contamination is an alarming problem, which poses a serious risk to human health and the surrounding geology. Soils get contaminated with heavy metals due to the un-regularized industrial discharge of the toxic metal-rich effluents. Under such a condition, the remediation of the contaminated sites becomes imperative for a sustainable, safe, and healthy environment. Phytoextraction, which involves the removal of heavy metals from the soil through root absorption and uptake, is a viable remediation technique, which ensures extraction of the toxic inorganic compound available in the soil even at low concentrations. The soil present in the Silghat Region of Assam, India, is mostly contaminated with Zinc (Zn) and Lead (Pb), having concentrations as high as to cause a serious environmental problem if proper measures are not taken. In the present study, an extensive experimental study was carried out to understand the effectiveness of two commonly planted trees in Assam, namely, i) Indian Pennywort and ii) Fenugreek, in the removal of heavy metals from the contaminated soil. The basic characterization of the soil in the contaminated site of the Silghat region was performed and the field concentration of Zn and Pb was recorded. Various long-term laboratory pot tests were carried out by sowing the seeds of Indian Pennywort and Fenugreek in a soil, which was spiked, with a very high dosage of Zn and Pb. The tests were carried out for different concentration of a particular heavy metal and the individual effectiveness in the absorption of the heavy metal by the plants were studied. The concentration of the soil was monitored regularly to assess the rate of depletion and the simultaneous uptake of the heavy metal from the soil to the plant. The amount of heavy metal uptake by the plant was also quantified by analyzing the plant sample at the end of the testing period. Finally, the study throws light on the applicability of the studied plants in the field for effective remediation of the contaminated sites of Assam.

Keywords: phytoextraction, heavy-metals, Indian pennywort, fenugreek

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Authors: Yaling Gou, Sucai Yang, Pengwei Qiao

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Integrated chemical-biological treatment is an attractive alternative to remove polycyclic aromatic hydrocarbons (PAHs) from contaminated soil; wherein indigenous bacteria is the key factor for the biodegradation of residual PAHs concentrations after the application of chemical oxidation. However, the systematical study on the impact of persulfate (PS) oxidation on indigenous bacteria as well as PAHs removal is still scarce. In this study, the influences of different PS dosages (1%, 3%, 6%, and 10% [w/w]), as well as various activation methods (native iron, H2O2, alkaline, ferrous iron, and heat) on PAHs removal and indigenous bacteria in highly contaminated aged soil were investigated. Apparent degradation of PAHs in the soil treated with PS oxidation was observed, and the removal efficiency of total PAHs in the soil ranged from 38.28% to 79.97%. The removal efficiency of total PAHs in the soil increased with increasing consumption of PS. However, the bacterial abundance in soil was negatively affected following oxidation for all of the treatments added with PS, with bacterial abundance in the soil decreased by 0.89~2.88 orders of magnitude compared to the untreated soil. Moreover, the number of total bacteria in the soil decreased as PS consumption increased. Different PS activation methods and PS dosages exhibited different influences on the bacterial community composition. Bacteria capable of degrading PAHs under anoxic conditions were composed predominantly by Proteobacteria and Firmicutes. The total amount of Proteobacteria and Firmicutes also decreased with increasing consumption of PS. The results of this study provide important insight into the design of PAHs contaminated soil remediation projects.

Keywords: activation method, chemical oxidation, indigenous bacteria, polycyclic aromatic hydrocarbon

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Authors: Somaye Eskandary

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Polycyclic aromatic hydrocarbons (PAHs) are present in crude oil and its derivatives contaminate soil and also increase carcinogen and mutagen contamination, which is a concern for researchers. Land farming is one of the methods that remove pollutants from the soil by native microorganisms. It seems that this technology is cost-effective, environmentally friendly and causes less debris problem to be disposed. This study aimed to refine the polycyclic aromatic hydrocarbons from oil-contaminated soil using the land farming method. In addition to examine the concentration of polycyclic aromatic hydrocarbons by GC-FID, some characteristics such as soil microbial respiration and dehydrogenase, peroxidase, urease, acid and alkaline phosphatase enzyme concentration were also measured. The results showed that after land farming process the concentrations of some polycyclic aromatic hydrocarbons dropped to 50 percent. The results showed that the enzyme concentration is reduced by reducing the concentration of hydrocarbons and microbial respiration. These results emphasize the process of land farming for removal of polycyclic aromatic hydrocarbons from soil by indigenous microorganisms.

Keywords: soil contamination, gas chromatography, native microorganisms, soil enzymes, microbial respiration, carcinogen

Procedia PDF Downloads 387

Authors: G. Petruzzelli, F. Pedron, M. Grifoni, M. Barbafieri, I. Rosellini, B. Pezzarossa

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As a result of diverse industrial activities, pollution from numerous contaminant affects both groundwater and soils. Many contaminated sites have been discovered in industrialized countries and their remediation is a priority in environmental legislations. The aim of this paper is to provide the evolution of remediation from consolidated invasive technologies to environmental friendly green strategies. Many clean-up technologies have been used. Nowadays the technologies selection is no longer exclusively based on eliminating the source of pollution, but the aim of remediation includes also the recovery of soil quality. “Green remediation”, a strategy based on “soft technologies”, appears the key to tackle the issue of remediation of contaminated sites with the greatest attention to environmental quality, including the preservation of soil functionality.

Keywords: bioremediation, Green Remediation, phytoremediation, remediation technologies, soil

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Authors: Mozhgan Farzami Sepehr, Farhad Nourozi

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In a greenhouse study, decontamination capacity of the species Polypogon monspoliensis, for detoxification of petroleum-polluted soils caused by sewage and waste materials of Tehran Petroleum Refinery. For this purpose, the amount of total oil and grease before and 45 days after transplanting one-month-old seedlings in the soils of five different treatments in which pollution-free agricultural soil and contaminated soil were mixed together with the weight ratio of respectively 1 to 9 (% 10), 2 to 8 (%20), 3 to 7 (%30) , 4 to 6 (%40), and 5 to 5 (%50) were evaluated and compared with the amounts obtained from control treatment without vegetation, but with the same concentration of pollution. Findings demonstrated that the maximum reduction in the petroleum rate ,as much as 84.85 percent, is related to the treatment 10% containing the plant. Increasing the shoot height in treatments 10% and 20% as well as the root dry and fresh weight in treatments 10% , 20% , and 30% shows that probably activity of more rhizosphere microorganisms of the plant in these treatments has led to the improvement in growth of plant organs comparing to the treatments without pollution.

Keywords: phytoremediation, total oil and grease, rhizosphere, microorganisms, petroleum-contaminated soil

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Authors: Mohammad Aladwan, Adelia Skripova

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Bioremediation aspects of crude oil-polluted fields can be achieved by isolation and identification of bacterial species from oil-contaminated soil in order to choose the most active isolates and increase the strength of others. In this study, oil-degrading bacteria were isolated and identified from oil-contaminated soil samples in northeastern Jordan. The bacterial growth count (CFU/g) was between 1.06×10⁵ and 0.75×10⁹. Eighty-two bacterial isolates were characterized by their morphology and biochemical tests. The identified bacterial genera included: Klebsiella, Staphylococcus, Citrobacter, Lactobacillus, Alcaligenes, Pseudomonas, Hafnia, Micrococcus, Rhodococcus, Serratia, Enterobacter, Bacillus, Salmonella, Mycobacterium, Corynebacterium, and Acetobacter. Molecular identification of a universal primer 16S rDNA gene was used to identify four bacterial isolates: Microbacterium esteraromaticum strain L20, Pseudomonas stutzeri strain 13636M, Klebsilla pneumoniae, and uncultured Klebsilla sp., known as new strains. Our results indicate that their specific oil-degrading bacteria isolates might have a high strength of oil degradation from oil-contaminated sites. Staphylococcus intermedius (75%), Corynebacterium xerosis (75%), and Pseudomonas fluorescens (50%) showed a high growth rate on different types of hydrocarbons, such as crude oil, toluene, naphthalene, and hexane. In addition, monooxygenase and catechol 2,3-dioxygenase were detected in 17 bacterial isolates, indicating their superior hydrocarbon degradation potential. Total petroleum hydrocarbons were analyzed using gas chromatography for soil samples. Soil samples M5, M7, and M8 showed the highest levels (43,645, 47,805, and 45,991 ppm, respectively), and M4 had the lowest level (7,514 ppm). All soil samples were analyzed for heavy metal contamination (Cu, Cd, Mn, Zn, and Pb). Site M7 contains the highest levels of Cu, Mn, and Pb, while Site M8 contains the highest levels of Mn and Zn. In the future, these isolates of bacteria can be used for the cleanup of oil-contaminated soil.

Keywords: bioremediation, 16S rDNA gene, oil-degrading bacteria, hydrocarbons

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Authors: Abubakar Aisami, Ahmad Deedat

Abstract:

Soil contamination by crude oil and other hydrocarbons poses significant environmental challenges due to its adverse effects on soil fertility and ecosystem health. Bioremediation, employing indigenous microorganisms, offers a promising and eco-friendly approach to mitigate such contamination. In this study, a bacteria from oil engine oil contaminated soil was isolated and characterized for crude oil degrading. Molecular identification of the isolated bacterial strains was conducted by 16S rRNA gene sequencing and phylogeny. Cultural conditions such as pH, temperature, crude oil concentration and salinity were tested in a mineral salt media containing crude oil sa the only carbon source. The isolate was identify as Enterobacter sp. Strain Deedat01 and was deposited at NCBI gene bank with accession number 0R026987.The optimal conditions for crude oil degradation were determined to be pH 8, temperature of 40°C, crude oil concentration of 9%, and salinity of 8%. Under these conditions, the isolated bacteria exhibited enhanced crude oil degradation efficiency. This study provides valuable insights into optimizing environmental conditions for the molecular identification and characterization of indigenous crude oil degrading bacteria isolated from engine oil contaminated soil.

Keywords: crude oil degradation, 16S rRNA, contamination, enterobacter sp, engine oil

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Authors: Rupa Rani, Vipin Kumar

Abstract:

Endosulfan, an organochlorine pesticide is of environmental concern due to its apparent persistence and toxicity. It has been reported as contaminants in soil, air, and water and is bioaccumulated and magnified in ecosystems. The combined use of microorganisms and plants has great potential for remediating soil contaminated with organic compounds such as pesticides. The objective of this study was to evaluate whether the bacterial inoculation influences plant growth promotion, endosulfan degradation in soil and endosulfan accumulation in different plant parts. Lycopersicon esculentum L. (Tomato) was grown in endosulfan spiked soil and inoculated with endosulfan tolerant bacterial strains. Endosulfan residues from different parts of plants and soil were extracted and estimated by using gas chromatograph equipped with 63Ni electron capture detector (GC-ECD). The inoculation of bacterial strains into the soil with plants showed a beneficial effect on endosulfan degradation and plant biomass production. Maximum endosulfan (90%) degradation was observed after 120 days of bacterial inoculation in the soil. Furthermore, there was significantly less endosulfan accumulation in roots and shoots of bacterial strains inoculated plants as compared to uninoculated plants. The results show the effectiveness of inoculated endosulfan tolerant bacterial strains to increase the remediation of endosulfan contaminated soil.

Keywords: organochlorine pesticides, endosulfan, degradation, plant-bacteria partnerships

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Authors: Miron A., Tadmor R., Pinkert S.

Abstract:

Soil contamination is a pressing environmental concern, drawing considerable focus due to its adverse ecological and health outcomes, and the frequent occurrence of contamination incidents in recent years. The interaction between the oil pollutant and the host soil can alter the mechanical properties of the soil in a manner that can crucially affect engineering challenges associated with the stability of soil systems. The geotechnical investigation of contaminated soils has gained momentum since the Gulf War in the 1990s, when a massive amount of oil was spilled into the ocean. Over recent years, various types of soil contaminations have been studied to understand the impact of pollution type, uncovering the mechanical complexity that arises not just from the pollutant type but also from the properties of the host soil and the interplay between them. This complexity is associated with diametrically opposite effects in different soil types. For instance, while certain oils may enhance the frictional properties of cohesive soils, they can reduce the friction in granular soils. This striking difference can be attributed to the different mechanisms at play: physico-chemical interactions predominate in the former case, whereas lubrication effects are more significant in the latter. this study introduces an empirical law designed to quantify the mechanical effect of oil contamination in granular soils, factoring the properties of both the contaminating oil and the host soil. This law is achieved by comprehensive experimental research that spans a wide array of oil types and soils with unique configurations and morphologies. By integrating these diverse data points, our law facilitates accurate predictions of how oil contamination modifies the frictional characteristics of general granular soils.

Keywords: contaminated soils, lubrication, friction, granular media

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Authors: Samira Abbaspour

Abstract:

Soil contamination by oil industry is unavoidable issue; irrespective of environmental impact, which occurs during the process of soil contaminating and remediating. Effect of this phenomenon on the geotechnical properties of the soil has not been investigated thoroughly. Some researchers studied the environmental aspects of these phenomena more than geotechnical point of view. In this research, compaction and unconfined compression tests were conducted on samples of natural, contaminated and treated soil after 50 days of bio-treatment. The results manifest that increasing the amount of crude oil, leads to decreased values of maximum dry density and optimum water content and increased values of unconfined compression strength (UCS). However, almost 65% of this contamination terminated by using a Bioremer as a bioremediation agent. Foremost, as bioremediation takes place, values of maximum dry density, unconfined compression strength and failure strain increase.

Keywords: contamination, shear strength, compaction, oil contamination

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Authors: E. Osazee, L. U. Bashir

Abstract:

This study was conducted at the Department of Biological Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria, to determine the effects of different weights of cow dung on indigenous bacterial isolates in remediation of crude oil contaminated soils. The soil (1kg) was contaminated with 20g of crude oil and this was treated with three (40g, 80g and 120g) weights of cow dung. The soils were amended after two weeks of crude oil contamination. Soil samples were collected from the plastic bags for microbiological analyses. The isolates were cultured to test their ability to grow on crude oil. The ability of the isolates to utilize the crude oil was determined using media dilution technique. Bacteria such as Proteus mirabilis, Bacillus lacterosporus, Morganella morganii, Serratia marcescens and Bacillus alvei were isolated. The variables measured were heterotrophic bacterial populations, hydrocarbon utilizing bacterial populations and the percentage of crude oil degraded in the soils. Data collected were subjected to analysis of variance (ANOVA). Results obtained indicated that all the different weights of cow dung showed appreciable effect in crude oil decontamination. Based on the findings of the experiments, it could be deduced that 120g of cow dung promoted higher degradation of hydrocarbons. Thus, it should be recommended for remediation of crude oil contaminated soil in the study area.

Keywords: crude oil, cow dung, amendment, bioremediation, decontamination

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