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The Kingdom of Saudi Arabia (KSA) is the leading oil-exploring and -exploiting country in the world. As a result, contamination of the environment by petroleum products (mainly hydrocarbons) is common, necessitating strategies for their removal from the environment. Much work has been conducted on bacterial degradation of hydrocarbons in the KSA. This review comprehensively analyzed 43 research investigation articles on bacterial hydrocarbon degradation, mainly polyaromatic hydrocarbons (PAHs) within the KSA. More than 30 different bacterial genera were identified that were capable of degrading simple and complex PAHs, including benzo[a]pyrene and coronene. Different strategies for selecting and isolating these bacterial strains and their advantages and disadvantages were highlighted. The review also discussed the origins of sample inocula and the contributions of various research groups to this field. PAH metabolites produced by these bacteria were presented, and biochemical pathways of PAH degradation were proposed. More importantly, research gaps that could enrich our understanding of petroleum product biodegradation mechanisms were highlighted. Overall, the information presented in this paper will serve as a baseline for further research on optimizing bioremediation strategies in all petroleum-contaminated environments. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Anning Refinery, a large-scale joint venture in southern China, possesses significant potential in regard to polluting local groundwater environments due to its extensive petroleum raw materials. This study aims to mitigate the substantial risks associated with oil spills and prevent consequential groundwater pollution by developing a robust groundwater flow model using the MODFLOW module in GMS software that aligns closely with natural and pumping test conditions. Furthermore, by integrating the MT3DMS model, a groundwater solute transport model is constructed and calibrated using sodium chloride tracer dispersion data. Notably, the wax hydrocracking unit and aviation coal finished product tank area are identified as key pollution sources warranting attention. By considering local constraints such as karst collapse, ground subsidence, and single-well water output capacity, the study introduces a tailored groundwater pollution management model. The research simulates various scenarios of petroleum pollutant migration in groundwater and proposes multi-objective emergency response optimization plans. In Scenario 1, simulations show that petroleum pollutants migrate within the unconfined aquifer and enter the karst aquifer as low-concentration plumes over an extended period. Detection of these plumes in karst water monitoring wells indicates upstream unconfined aquifer contamination at higher concentrations, necessitating immediate activation of the nearest monitoring or emergency wells in both layers. Conversely, in Scenario 2, pollutants reside briefly in the unconfined aquifer before entering the karst aquifer at relatively higher concentrations. Here, low-efficiency pollutant discharge through unconfined aquifer monitoring wells prompts the activation of nearby karst aquifer monitoring or emergency wells for effective pollution control. This model underscores the necessity for proactive monitoring and validates the efficacy of coupled numerical modeling in understanding pollutant behavior, offering valuable insights into pollution control scenario assessments. In summary, the study emphasizes the importance of targeted monitoring and emergency protocols, demonstrating the benefits of integrated modeling approaches in industrial areas prone to pollution risks, and provides critical theoretical and practical guidance for groundwater protection and pollution management, offering transferable insights for similar industrial settings worldwide. [ABSTRACT FROM AUTHOR]

The Kingdom of Saudi Arabia (KSA) is the leading oil-exploring and -exploiting country in the world. As a result, contamination of the environment by petroleum products (mainly hydrocarbons) is common, necessitating strategies for their removal from the environment. Much work has been conducted on bacterial degradation of hydrocarbons in the KSA. This review comprehensively analyzed 43 research investigation articles on bacterial hydrocarbon degradation, mainly polyaromatic hydrocarbons (PAHs) within the KSA. More than 30 different bacterial genera were identified that were capable of degrading simple and complex PAHs, including benzo[a]pyrene and coronene. Different strategies for selecting and isolating these bacterial strains and their advantages and disadvantages were highlighted. The review also discussed the origins of sample inocula and the contributions of various research groups to this field. PAH metabolites produced by these bacteria were presented, and biochemical pathways of PAH degradation were proposed. More importantly, research gaps that could enrich our understanding of petroleum product biodegradation mechanisms were highlighted. Overall, the information presented in this paper will serve as a baseline for further research on optimizing bioremediation strategies in all petroleum-contaminated environments.

Surfactant‐free microemulsions (SFMEs) cleaning technology can effectively separate and recover petroleum pollutants from oil‐based drilling cuttings (OBDCs). The identification of the molecular composition of OBDCs is helpful to accurately grasp the conversion mechanism of organic matter. Therefore, the understanding of the mechanism of petroleum removal at the microscopic molecular level in the cleaning process needs to be further studied. The conversion mechanism of organic matter during the use of SFMEs to clean OBDCs was investigated by positive ion atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (+APPI FT‐ICR MS). The results show that the SFMEs cleaning technology can separate and recover CH and CHO organic matter in OBDCs, but there is still a small amount of organic matter with high molecular weight and unsaturated degree in OBDCs that has not been separated. The majority of this organic matter is CH, accounting for 91 %, and it is mainly polycyclic aromatic hydrocarbons. A total of 255 kinds of organic matter in 110# industrial white oil were detected in the recovered oil after treatment, accounting for more than 99 % of the total, which has a certain recoverable value. This study can provide a theoretical reference for the efficient degradation of OBDCs. [ABSTRACT FROM AUTHOR]

Runoff is one of the most important hydrological processes in ecosystems, which is very important in the management of water and soil resources. Although the use of soil microorganisms as soil inoculants in the bioengineering management of runoff has been confirmed, the use of soil microorganisms to control runoff in soils contaminated with petroleum has not been considered. Therefore, in order to evaluate inoculation of soil Bacteria, Cyanobacteria and fungi in reducing runoff in soil contaminated with petroleum, the present study was carried at plots of 0.5×0.5 m with slope of some 25% and level of 20000 mg kg-1 of gasoil and control contamination in three replicates. The plots will be then subjected to rainfall intensity of some 35 mm h−1 and duration of 30 min installed at the Rainfall Simulation Laboratory of Tarbiat Modares University at Faculty of Natural Resources. The results showed that the inoculation treatments, although there was no significant difference compared to the control treatment (P>0.05) except for the start of runoff (P<0.05), improved the components of runoff. The comparison of the mean of the study variables showed that the bacteria, cyanobacteria, fungi, bacteria+fungi, bacteria+cyanobacteria, cyanobacteria+fungi, and bacteria+cyanobacteria+fungi caused +47.10, -0.08, -10.72, -24.86, +14.85, +49.88 and +27.88 percent changes in runoff start time, +4.58, -54.04, +65.19, +72.20, -41.36, -84. 53 and +40.15 percent changes in runoff volume, and +4.75, +54.06 and - 65.15, +72.28, -41.39 and -84.55 and +40.20 percent changes in runoff coefficient, respectively. The results of the research indicated the relative synergistic performance of the combination treatment of cyanobacteria + fungi in reducing the effect of gasoil on runoff properties. Finally, the results of the present study showed that the inoculation of native soil bacteria, cyanobacteria, and fungi can be an efficient and sustainable biological technology to improve runoff characteristics in areas contaminated with petroleum. [ABSTRACT FROM AUTHOR]

The consumption of oils and related derivatives has dramatically increased during the period of rapid development of global industrialization and urbanization in the last few decades. In the process of petroleum extraction, transportation, processing and utilization, the leakages of petroleum into soils are almost inevitable, due to imperfect management, incomplete combustion, leakage from aging pipelines and other accidental factors. Owing to the certain toxicity of petroleum and related derivatives, petroleum pollutants in soils can cause serious local environmental and human health issues. Consequently, effective soil remediation technologies of oil-contaminated sites are crucially demanded for sustainable development and environmental safety. This review introduces the current situation of oil-contaminated sites, and discusses various soil remediation strategies and corresponding treatment mechanisms. In addition, the advantages and limitations of every remediation technology are summarized in detail. Generally speaking, although physical remediation and chemical remediation have the advantage of short operation time, exorbitant operating cost, complex equipment and suitable chemicals are required. However, owing to the complexity of contaminated site conditions, single remediation technology cannot satisfy all types of oil-contaminated sites. Meanwhile, biological remediation and combined remediation technologies are highlighted, which are the direction of future development trend under complex pollution conditions of oil-contaminated sites. Finally, challenges in remediation of oil-contaminated sites such as soil variation, site conditions, site responsibility, remediation funding and future development recommendations are discussed, which might provide new horizons and reference information for future soil remediation work of oil-contaminated sites.

In this paper, we evaluated the potential of two synthesized bio-based polyurethane foams, PU1 and PU2, for the removal of diesel and gasoline from water mixtures. We started the investigation with the experiment in batch. The total sorption capacity S (g/g) for the diesel/water system was slightly higher with respect to gasoline/water, with a value of 62 g/g for PU1 and 65 g/g for PU2. We found that the sorption follows a pseudo second-order kinetic model for both the materials. The experimental data showed that the best isotherm models were obtained with Langmuir and Redlich–Peterson models. In addition, to provide an idea of the process scalability for future industrial applications, we tested the sorption capacity of the foams using a continuous-flow of the same oil/water mixtures and we obtained performances even better with respect to the batch test. The regeneration can be performed up to 50 times by centrifuge, without losing efficacy. [ABSTRACT FROM AUTHOR]

Oil-based drilling cuttings (OBDC) have a high content of petroleum pollutants with strong mutagenic, carcinogenic and teratogenic properties. Solvent extraction can effectively separate petroleum pollutants from OBDC. However, single solvent has preferred solubility for different types of petroleum pollutants in OBDC, resulting in a lower oil removal efficiency. Therefore, based on the polarity difference between methanol (Me) and n-hexane (He), a method was developed to extract petroleum pollutants from OBDC using Me&He. Compared with methanol or n-hexane alone, the oil removal efficiency of compound Me&He was significantly increased to 94.58 %, and 37, 37 and 77 petroleum pollutants were extracted using Single methanol, Single n-hexane and Compound Me&He, respectively. Methanol extraction preferentially solubilised polar molecules such as alcohols and carboxylic acids, while n-hexane extraction preferentially solubilised alkanes and other nonpolar molecules. Compound Me&He compensated for the low solubility of single solvents for petroleum pollutant extraction from OBDC. Additionally, because methanol and n-hexane are not mutually soluble, it was easy to separate the recycled components. Compared with other common solvent extraction technologies, compound Me&He had advantages including simple operation and high oil removal efficiency. This study provided a theoretical basis and technical reference for the efficient processing and resource recycling of OBDC. • Methanol and n-hexane are applied to extract petroleum pollutants from OBDC. • Compound solvent compensates for the low oil removal efficiency of single solvents. • Compounds recovered by methanol&n-hexane solvent are identified. • The influential factors and the extraction mechanisms are investigated. [ABSTRACT FROM AUTHOR]

Biological markers (BMs) are organic compounds in oils in which a precursor is known, and during the transformation of organic matter these compounds undergo certain structural and stereochemical changes. Based on the established precursors of BMs, the origin of the examined oils can be estimated, and based on the intensity and the type of changes and also geological history. It includes defining the deposition medium, the degree of maturation, the length of the oil migration path, the degree of biodegradation. The most studied and applied BMs are normal alkanes, isoprenoid aliphatic alkanes pristane and phytane, and polycyclic alkanes of the sterane and terapane type. On the other hand, in the environmental chemistry, these compounds can significantly contribute to the identification of petroleum pollutants, as well as to the assessment of the migration mechanism and the intensity of biodegradation. This review paper first presents the results related to the application of BMs in the organic geochemical correlations of oil in the south-eastern part of the Pannonian Basin (I). The second part provides an overview of those researches in which the same BMs were used in the identification of oil pollutants and in monitoring their changes during the migration and the biodegradation in rivers and river sediments of Serbia (II).

Laser-induced fluorescence technology is an effective method for detecting oil pollutants. The laser induced fluorescence detection system was developed, and four parallel microchannel sample pools were designed to improve the detection accuracy of fluorescence signals. The grating scanning system is improved by introducing grating feedback link to improve the wavelength scanning accuracy of the system.The experimental results show that the wavelength scanning resolution of the microchannel laser-induced fluorescence detection system is improved by 0.4 nm. Aiming at the defects of the traditional parallel factor algorithm which is sensitive to the sample components, slow operation speed and easy to fall into local convergence, the generalized inverse singular value decomposition is used to improve the parallel factor algorithm. Configure different concentrations of diesel, gasoline and kerosene solution samples. The experimental verification shows that the excitation-emission spectra of each component obtained by the improved parallel factor algorithm are highly consistent with the measured spectral characteristics, indicating that the microchannel laser-induced fluorescence detection system combined with the improved parallel factor analysis method can accurately identify oil pollutants.

Abstract Over the past decades, a large amount of petroleum pollutants has been released into the environment resulting from various activities related to petrochemicals. The discharge of wastewater with petrochemicals can pose considerable risk of harm to the human health and the environment. The use of adsorbents has received much consideration across the environmental field as an effective approach for organic pollutant removal. There is a particular interest in the use of biomass adsorbent as a promising environmentally-friendly and low-cost option for removing pollutants. In this article, we present a review of biomass-derived adsorbents for the removal of petroleum pollutants from water. The features of different adsorbents such as algae, fungi, and bacteria biomasses are summarized, as is the process of removing oil and PAHs using biomass-derived adsorbents. Finally, recommendations for future study are proposed.

Growing concerns about water pollution and its potentially harmful effects on human being have stimulated serious efforts to develop reliable biological monitoring techniques. The bioluminescent analysis is one of the most promising approaches for the biomonitoring of the environment, due to the sensitivity of the luminescent system to even micro quantities of the pollutants. The aim of the current study was to assess the petroleum compounds toxicity using Vibrio fischeri bacterium. The growth pattern of the bacterium was determined in photobacterium broth using the optical density measurement at 600 nm, which showed the optimum growth time of 16-18 hours after inoculation. In this research, the effects of environmental parameters such as temperature, pH and various concentrations of oil on the growth and luminescence of Vibrio fischeri were examined. The results revealed that the optimum growth conditions of the bacterium after 16 hours included the temperature of 25 °C and pH 7. Besides, the growth and luminescence intensity of Vibrio fischeri were a function of total petroleum hydrocarbon concentrations in the medium, which were significantly reduced in oil concentrations by more than 4% w/v. Therefore, the Vibrio fischeri could, therefore, have the potential for monitoring of petroleum pollutants in the aqueous media.

Herein, for the determination of trace amounts of five petroleum pollutants (TLU, OCT, p-XY, o-XY and AN) in the water samples with complex matrices, first of all, the glass fibers sheet was applicated as a supporting substrate and then the GLA/SO/FS/Ag NPs/AC electrospun nanofibers was prepared (17 kV, 12 cm, 2 μL min−1) on this substrate. Subsequently, the photo crosslinking was accomplished at λ= 366 nm. In the next step, these nanofibers were used as a sorbent under the spin column-micro solid phase extraction (SC-μSPE) of five petroleum pollutants in the sea water, farm water and drinking water samples under obtained optimum conditions with design expert software and on at a time (OAT) method. [Display omitted] • The electrospun nanofibers (GLA/SO/FS/Ag NPs/AC) were used as a sorbent in SC-μSPE. • The preconcentrated solution of five petroleum pollutants was injected into GC-FID. • The optimization step was accomplished with both the design expert and OAT. • The amounts of 5 petroleum pollutants were determined in the various water samples. Herein, green electrospun nanofibers were prepared based on gelatin/soybean oil/fumed silica/Ag NPs/activated carbon (GLA/SO/FS/Ag NPs/AC). Then, the nanofibers were used as an efficacious sorbent in the spin-column-micro solid-phase extraction (SC-µSPE) of trace amounts of five petroleum pollutants (toluene, n-octane, p-xylene, o-xylene, and aniline). The mentioned pollutants were measured in various water samples using GC-FID. GLA/SO/Ag NPs/FS/AC electrospun nanofibers were characterized using field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy with elemental mapping analysis (EDX-Mapping), Brunauer-Emmett-Teller (BET) surface analysis, Fourier transform-infrared (FT-IR), and X-ray diffraction (XRD), confirming the synthesis of the composite nanofibers. Factors affecting the adsorption and desorption process of SC-µSPE were optimized using design-expert 12.0 software and the one-at-a-time method. A wide linear range of 3–1100 ng mL−1 with R2 ≥ 0.9883 was achieved under the optimum conditions, along with low detection limits ranging from 1.08 to 6.8 ng mL−1 based on S/N = 3 and significant enrichment factors. Intra-day and inter-day RSDs% ranged from 4.23 % to 5.77 % and 5.72 % to 7.39 %, respectively. Lastly, the efficiency of the SC-µSPE method was evaluated to determine these five petroleum pollutants in various water samples, yielding good recoveries ranging from 94.2 % to 102.6 %. [ABSTRACT FROM AUTHOR]

Background: : Lead (Pb) is an important environmental pollutants that play a significant role in increasing the stability of some other pollutants by changing the microbial profile of the soil. Bacillus subtilis WPI is an abundant bacteria existing in wastewater. Because of laccase enzyme in this bacterium, the decomposition process of aromatic pollutants in wastewaters can be facilitated. We aimed to investigate the effect of different Pb concentrations on B. subtilis growth and biological activity of laccase enzyme in B. subtilis WPI. Material and Methods: B. subtilis WPI was isolated from the paper mill industrial wastewater of Hormozgan, Iran, from March to August 2017. After purification, the growth trend of B. subtilis WPI as well as the activity of laccase enzyme in different concentrations of Pb was investigated based on kinetic method. Results: Bacterial growth at Pb concentration of 400 mg/L reduced in a dose-dependent manner, and this decrease was significant at concentrations of 300 and 400 mg/L (P < 0.001). The level of laccase enzyme activity in the lead concentration range of 20-160 mg/L also reduced in a dose-dependent manner, which implied that the highest decrease was observed at lead concentration of 160 mg/L (P < 0.01). Our findings showed that there was no significant change in bacterial growth in lead concentration range of 20-200 mg/L, while a significant change was observed in the activity of laccase enzyme in the mentioned concentration range. Conclusion: Therefore, it seems that this reduction in enzyme activity can indirectly increase the stability of aromatic oil pollutants in the environment.

Soil contamination by petroleum contaminants and their derivatives has harmful effects on the environment, including groundwater and marine contamination and on the geotechnical properties of the soil. It decreases the soil strength, bearing capacity of foundations, and slope and trench stability. Petroleum contaminants can also alter the structure of cohesive granular soil. The present study examined the effect of acidic sludge and dirt filter contaminants from a burnt oil refinery on the compaction parameters and strength of clayey sand. Proctor compaction and direct shear tests were performed on soil samples containing 0%, 3%, 6%, and 9% of these pollutants. Direct shear tests were performed at different depths and stresses on soil samples from sandy soil contaminated with the residue from a burnt oil refinery. The results showed that with approximately 4 to 5% increase in pollution, the maximum dry soil unit weight increases and decreases with the addition of more contaminants. Also, the friction and dilatancy angles of the soil decreased. The sample containing 9% pollutants recorded the most significant decrease in these values. The effect of surface-active agents on acidic sludge caused an increase in the Van der Waals force between the particles, resulting in an increase in soil cohesion. Contamination with 47.7% SiO2 from the dirt filter increased the soil cohesion parameter. Under similar experimental and loading conditions, an increase in the acidic sludge and dirt filter contents decreased the soil shear strength and dilatancy angle. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over the past decades, a large amount of petroleum pollutants has been released into the environment resulting from various activities related to petrochemicals. The discharge of wastewater with petrochemicals can pose considerable risk of harm to the human health and the environment. The use of adsorbents has received much consideration across the environmental field as an effective approach for organic pollutant removal. There is a particular interest in the use of biomass adsorbent as a promising environmentally-friendly and low-cost option for removing pollutants. In this article, we present a review of biomass-derived adsorbents for the removal of petroleum pollutants from water. The features of different adsorbents such as algae, fungi, and bacteria biomasses are summarized, as is the process of removing oil and PAHs using biomass-derived adsorbents. Finally, recommendations for future study are proposed. [ABSTRACT FROM AUTHOR]

Growing concerns about water pollution and its potentially harmful effects on human being have stimulated serious efforts to develop reliable biological monitoring techniques. The bioluminescent analysis is one of the most promising approaches for the biomonitoring of the environment, due to the sensitivity of the luminescent system to even micro quantities of the pollutants. The aim of the current study was to assess the petroleum compounds toxicity using Vibrio fischeri bacterium. The growth pattern of the bacterium was determined in photobacterium broth using the optical density measurement at 600 nm, which showed the optimum growth time of 16-18 hours after inoculation. In this research, the effects of environmental parameters such as temperature, pH and various concentrations of oil on the growth and luminescence of Vibrio fischeri were examined. The results revealed that the optimum growth conditions of the bacterium after 16 hours included the temperature of 25 °C and pH 7. Besides, the growth and luminescence intensity of Vibrio fischeri were a function of total petroleum hydrocarbon concentrations in the medium, which were significantly reduced in oil concentrations by more than 4% w/v. Therefore, the Vibrio fischeri could, have the potential for monitoring of petroleum pollutants in the aqueous media. [ABSTRACT FROM AUTHOR]

Soil contamination with petroleum significantly threatens the ecological equilibrium and human health. In this context, aerobic co-composting of waste heavy oil with agricultural wastes was performed in the present study to remediate petroleum pollutants through four treatments: CK (control), T1 (petroleum pollutant), T2 (petroleum pollutant with bentonite), and T3 (petroleum pollutant with humic acid-modified bentonite). Comprehensive analyses were conducted to determine the physicochemical parameters, enzymatic activities, removal of petroleum pollutants, microbial community structure, and water-extractable organic matter in different composting systems. Structural equation modeling was employed to identify the key factors influencing the removal of petroleum pollutants. According to the results, petroleum pollutant removal percentages of 44.94%, 79.09%, and 79.67% could be achieved with T1, T2, and T3, respectively. In addition, the activities of polyphenol oxidase (51.21 U/g) and catalase (367.91 U/g), which are the enzymes related to petroleum hydrocarbon degradation, were the highest in T3. Moreover, bentonite addition to the treatment increased the nitrate nitrogen storage in the compost from 10.95 mg/kg in T1 to 18.63 and 17.41 mg/kg in T2 and T3, respectively. Humic acid-modified bentonite could enhance the degree of compost humification, thereby leading to a higher-quality compost product. Collectively, these findings established bentonite addition as an efficient approach to enhance the compost remediation of petroleum pollutants. [Display omitted] • Bentonite improved microbial activity in compost by increasing nitrogen retention. • Bentonite compost product could be used for degradation of petroleum pollutant. • Degradation of petroleum pollutant predominantly relied on biodegradation pathway. • Humic acid-modified bentonite promoted humification of compost products. [ABSTRACT FROM AUTHOR]

In this paper an applied organic geochemical approach in studying the nature of organic matter (OM) in water and sediments of the River Ibar (upsteream and downstream of towns Kosovska Mitrovica and Kraljevo) was used. A forensic approach that relies on the fact that the composition of OM of recent sediments and oil varies due to geological age and maturity was applied. The content of bitumen, its group composition of saturated, aromatic and NSO compounds (nitrogen, sulphur, and oxygen compounds) and the distribution of n-alkanes in saturated fractions identified by gas chromatography–mass spectrometry (in almost all samples incorporated into the colloidal micelles formed by water and NSO compounds) could not answer the question whether OM in isolated extracts has native or anthropogenic origin. However, the presence of sterane and terpane, with the distribution of structural and stereochemical isomers characteristic of oil, as a form of most matture OM in sediments, unambiguously confirmed presence of oil type pollutants in anlayzed samples. Based on significant differences in the distributions of these polycyclic alkane (water–water, sediment–sediment and water–sediment), it was concluded that they have more than one source of pollution, and that the River Ibar is permanently exposed to this form of pollution. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 176006]

Typha latifolia-planted vertical subsurface flow constructed wetlands (VSSF CWs) and an unplanted microcosm constructed wetland were used for treating secondary refinery wastewater from the Kaduna Refining and Petrochemical Company (KRPC, Nigeria). Cow dung was applied to the planted wetlands at the start of the experiment and after 3 months to enhance plant growth and petroleum degradation. The T. latifolia-planted VSSF CWs removed 45-99% total petroleum hydrocarbon (TPH), 99-100% phenol, 70-80% oil and grease, 45-91% chemical oxygen demand (COD), and 46-88% total suspended solids (TSSs). The performance of the unplanted control VSSF CW achieved lower removal efficiencies (15-58% TPH, 86-91% phenol, 16-44% oil and grease, 24-66% COD, and 20-55% TSS). T. latifolia plants had a bioaccumulation factor (BAF) > 1 for phenol, total nitrogen (TN), and total phosphate (TP), suggesting a high removal performance for these contaminants and good translocation ability (TF) for TPH, phenol, oil and grease, and TN, with the exception of TP which was mainly retained in their roots (BAF = 47). This study showed T. latifolia is a good candidate plant to be used in VSSF CWs for polishing secondary refinery wastewater in developing countries. [ABSTRACT FROM AUTHOR]

Electro-osmosis has been well recognized as a technique for the remediation of petroleum-contaminated soil, however seasonally freezing and thawing adds the complexity of petroleum mobility in cold regions. To investigate the influence of freeze-thaw on the electroosmotic removal of petroleum and explore the enhancement of freeze-thaw on the electroosmotic remediation efficiency in remediating the petroleum-contaminated soils, a set of laboratory tests were performed in three types of treatment modes, freeze-thaw (FT), electro-osmosis (EO) and freeze-thaw combined electro-osmosis (FE). The petroleum redistributions as well as the moisture content changes after the treatments were evaluated and compared. The petroleum removal rates of the three treatments were analyzed, and the underlying mechanisms were elaborated. The results indicated that the overall efficiency of the treatment mode regarding petroleum removal from soil followed the order of FE > EO > FT, corresponding to 54%, 36% and 21% in maximum, respectively. A considerable amount of water solution with surfactant was driven into contaminated soil during FT process, but the petroleum mobilization primarily occurred inside of the specimen. A higher remediation efficiency was yield in EO mode, but the induced dehydration and cracks leaded to the dramatical depression in the efficiency in further process. It is proposed that the petroleum removal is closely related to the flow of water solution with surfactant that is favorable to the solubility and mobilization of the petroleum in soil. Thus, the water migration induced by freeze-thaw cycles substantially improved the efficiency of the electroosmotic remediation in FE mode that gave the best performance for the remediation of the petroleum-contaminated soil. [Display omitted] • Three treatment modes were tested to study the remediation of oil in soils. • Water content rise by freeze-thaw improved electro-osmotic remediation efficiency. • Freeze-thaw and electro-osmosis method is satisfying to repair oil-polluted soil. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Efficient elimination of organic pollutants from wastewater is of great importance for sustainable human development. In this work, we report the fabrication of oleophilic porous activated sludge loading with microorganism (OPAS-M), which was prepared through multi-step doping of the microorganism into the as-prepared porous network of activated sludge (AS) followed by a hydrophobic surface modification, so that it has selective adsorption properties to achieve oil-water separation in oily wastewater and high effective degradation organic pollutions. Thanks to its abundantly porous structure and oleophilic wettability, the petroleum pollutants in wastewater (using n-hexadecane as model compound) can be selectively absorbed inside the OPAS-M and then could be biodegraded by the loaded microorganism. Compared with that of free microbial and porous activated sludge loading with microorganism (PSA-M) which has a degradation efficiency of 58.80% and 74.37%, respectively, the OPAS-M possesses a higher removal efficiency of 84.7%. The degradation kinetics of free microorganism, PAS-M and OPAS-M all fit well with the first-order kinetic equation, their degradation half-life is measured to be 7.44 d, 3.56 d, and 2.23 d, respectively. In addition, OPAS-M has good stability and tolerance, and the degradation efficiency can reach more than 50% in a poor environment. The degradation mechanism of n-hexadecane was studied by GC-MS. The results showed that n-hexadecane was selectively adsorbed to the interior of OPAS-M, and it was be degraded by enzymes in microorganism into n-hexadecanol、n-hexadecaldehyde and n-hexadecanoic acid in turn, and finally converted to water and carbon dioxide. The combination of selective absorption and biodegradable OPAS-M may open up a green and efficient way in the biological remediation of organic pollutants. [Display omitted] • Oleophilic porous activated sludge loading with microorganisms (OPAS-M) was prepared. • OPAS-M has selective adsorption ability of organic pollutants from waste water. • OPAS-M can rapidly degrade the model organic pollution with high efficiency. • Harmful organic pollution can be spontaneously converted into H 2 O and CO 2 by OPAS-M. • OPAS-M has better tolerance in various environments. [ABSTRACT FROM AUTHOR]

Petroleum contamination surrounding oilfields has attracted more concerns. However, the levels, distribution and source of petroleum of Changqing Oilfield soil still remain lots of knowns, which is important for local environmental protection. Given soil contamination issues in Changqiong Oilfield were investigated. The maximum concentrations of total petroleum hydrocarbons (TPHs), N-alkanes (TNAs) and polycyclic aromatic hydrocarbons (PAHs) were determined to be 1960.29, 96.13 and 0.82 mg/kg, respectively. TPHs were higher in the north than the south of the study area. TPHs decreased in the horizontal and vertical distribution as soil depth and distance from oil wells increased. Source analysis showed that TNAs mainly originated from petroleum, PAHs were controlled by petroleum spills, combustion and traffic. Correlation analysis implied that TPHs residues had an effect on soil environmental quality. This study have important implications for understanding the environmental behavior of petroleum and can provide support for petroleum remediation and risk control. [Display omitted] • TPHs in northern study area (QC, XF) were higher than those in the southern (PCQ). • TPHs levels obviously decreased with increasing soil depth and distance from the oil well. • The sources of TNAs and PAHs are oil leaking, coal combustion and vehicle exhaust. • TPHs residues had a negative effect on soil environmental quality. [ABSTRACT FROM AUTHOR]

The effect of natural attenuation, biostimulation and bioaugmentation-biostimulation on the removal of petroleum pollutants, specifically Total Petroleum Hydrocarbons (TPH), as well as Polycyclic Aromatic Hydrocarbons (PAHs) in a refinery solid waste was estimated. The experimental procedure took place on a laboratory scale in three separate tanks (natural attenuation, biostimulation and biostimulation-bioaugmentation tank) for a period of 80 days. Optimal conditions of temperature, humidity and ventilation were applied in order to ensure an efficient performance of the microdigesters. According to the results, addition of indigenous microorganisms and nutrients in biostimulation-bioaugmentation tank, proved to be particularly effective on the biodegradation of petroleum pollutants, achieving a removal efficiency of 52 and 87% for TPH and PAHs, respectively. In the biostimulation tank, the efficiency of TPH and PAHs removal was 47 and 59%, accordingly. Less effective appeared to be the natural attenuation process with a reduction efficiency of 37% for TPH and 42% for PAHs. [ABSTRACT FROM AUTHOR]