Remediation Of Hydrocarbon Contaminated Soils Research Articles

Slow-release microencapsulates containing nanoliposomes for bioremediation of soil hydrocarbons contaminated

ABSTRACT Encapsulation and nutrient addition in bacterial formulations have disadvantages concerning cell viability during release, storage, and under field conditions. Then, the objective of this work was to encapsulate a bacterial consortium with hydrocarbon-degrading capacities in different matrices composed of cross-linked alginate/ polyvinyl alcohol /halloysite beads (M1, M2, and M3) containing nanoliposomes loaded with or without nutrients and evaluate their viability and release in a liquid medium, and soil (microcosmos). Also, evaluate their capacity to remove total petroleum hydrocarbons (TPH) for 165 days and matrices characterization. The encapsulate consortium showed a quick adaptation to contaminated soil and a percentage of removal (PR) of TPH up to 30% after seven days. All the matrices displayed a PR of up to 90% after 165 days. The matrix M2 displayed significant resistance to degradation and higher cell viability with a PR of 94%. This result supports the encapsulation of bacteria in a sustainable matrix supplemented with nutrients as a well-looked strategy for improving viability and survival and, therefore, enhancing their effectiveness in the remediation of hydrocarbon-contaminated soils.

Biosolids-derived biochar enhances the bioremediation of diesel-contaminated soil

Biochar, a low-cost carbonaceous product, is gaining relevance in the remediation of hydrocarbon-contaminated soil. Current literature has shown that biochar studies have been carried out under different conditions. Although some attempts have been made to assess the effect of varying conditions in biochar-based remdediation studies, no work has assessed the effect of biochar pyrolysis temperature, biochar dose, and fertiliser dose altogether on the efficacy of biosolids-derived biochar in the remediation of diesel-contaminated soil, despite the fact that the influence of these parameters on the efficacy of the remediation process are likely to be significant. This study aimed to investigate the effect of biosolids-derived biochar on the remediation and ecotoxicity of diesel-contaminated soil, as well as to assess the influence of biochar pyrolysis temperature, biochar dose, and fertiliser addition on soil remediation. After 12 weeks, the contaminated soil amended with biochar produced at 900 °C and applied at 10% together with 1% fertiliser had a TPH concentration lower than the EPA Victoria maximum threshold for Category D waste (5000 mg/kg); in contrast, the TPH concentration in the control exceeded this threshold. Further, soil ecotoxicity at week 12 was lower in most of the biochar treatments. The alkB gene copy numbers increased at week 12 in almost all treatments. Hydrocarbon removal and soil ecotoxicity was affected by the studied factors. This study demonstrated the potential of biosolids biochar as a low-cost treatment to enhance the bioremediation of diesel-contaminated soils, while showing the importance of the treatment conditions on the biochar efficacy in remediation.

Biosurfactants production using glucose and molasses as carbon sources by Azotobacter vinelandii and soil washing application in hydrocarbon-contaminated soil

The purpose of this research was to understand the influence of carbon source variation in the biosurfactant production by Azotobacter vinelandii as well as its potential application on remediation of hydrocarbon-contaminated soil by soil washing. The growth microorganism, biosurfactant quantity in exopolysaccharide and fatty acid fraction were examined. The quality of biosurfactant was analysed by emulsification index. The results show that biggest production was occurred at the 48th hour with μmax1 = 0.416/hour, μmax2 = 0.093/hour and Ks1 = 6.55 g/L, Ks2 = 4.69 g/L for glucose and molasses substrate respectively. Biosurfactant product of Azotobacter vinelandii in glucose 1.5%, 2%, 2.5%, and 3% showed emulsification index as much as 100%. While, emulsification index of the biosurfactant produced with molasses reached 100% within 1%, 1.5%, and 2% molasse concentration. These results showed that molasses has potential utilization as carbon source in biosurfactant production. In soil washing application, Biosurfactant and Tween 80 were used as emulsifier to removed Total Petroleum Hydrocarbons (TPH) by contacting in conical flask at rotary shaker. The results showed that highest removal achieved by using biosurfactant up to 48.89% which occurred at 100 rpm for 40 minutes.

Thermal Treatment of Hydrocarbon-Impacted Soils: A Review of Technology Innovation for Sustainable Remediation

Abstract Thermal treatment technologies hold an important niche in the remediation of hydrocarbon-contaminated soils and sediments due to their ability to quickly and reliably meet cleanup standards. However, sustained high temperature can be energy intensive and can damage soil properties. Despite the broad applicability and prevalence of thermal remediation, little work has been done to improve the environmental compatibility and sustainability of these technologies. We review several common thermal treatment technologies for hydrocarbon-contaminated soils, assess their potential environmental impacts, and propose frameworks for sustainable and low-impact deployment based on a holistic consideration of energy and water requirements, ecosystem ecology, and soil science. There is no universally appropriate thermal treatment technology. Rather, the appropriate choice depends on the contamination scenario (including the type of hydrocarbons present) and on site-specific considerations such as soil properties, water availability, and the heat sensitivity of contaminated soils. Overall, the convergence of treatment process engineering with soil science, ecosystem ecology, and plant biology research is essential to fill critical knowledge gaps and improve both the removal efficiency and sustainability of thermal technologies.

Enhanced Degradation of Petroleum Hydrocarbons in Corn-Steep-Liquor-Treated Soil Microcosm

The efficiency of corn steep liquor (CSL) as a potential stimulant for remediation of hydrocarbon-contaminated soil was evaluated in soil microcosms. Chronically polluted soil samples treated with CSL, water, and un untreated control were compared over a period of 42 days. There were remarkable changes in the physicochemical status of the soil in the CSL-treated set-up with noticeable utilization of essential nutrients such as nitrogen, phosphorus, and potassium. Percentage hydrocarbon utilizers showed a concomitant increase with hydrocarbon utilization in CSL-treated (0.05–0.16%) and water-treated (0.02–0.12%) set-ups, while no significant changes occurred in the untreated control. Gas chromatographic fingerprints showed complete disappearance of the lower-fraction alkanes C7, C8, C9, and C11 within 21 days, as well as some higher fractions, significantly C16 and C29, in the CSL-treated set-up. In the CSL-treated set-up, 77.9% of hydrocarbon was degraded, while the corresponding values for the water-treated and untreated control were 40.55 and 30.6%, respectively. The percentage aliphatic components degraded differed significantly in the CSL-treated, water-treated, and untreated set-ups. The n-C17/pristane and n-C18/phytane ratios in the CSL-treated set-up were 1.298 and 1.153, respectively, on day 0, but at the end of the treatability period, the values had dropped drastically to 0.182 and 0.585, respectively. The results of this study show that corn steep liquor is a potential material for bioremediation of hydrocarbon-polluted sites.

Remediation of hydrocarbon-contaminated soils by ex situ microwave treatment: technical, energy and economic considerations

In this study, the remediation of diesel-polluted soils was investigated by simulating an ex situ microwave (MW) heating treatment under different conditions, including soil moisture, operating power and heating duration. Based on experimental data, a technical, energy and economic assessment for the optimization of full-scale remediation activities was carried out. Main results show that the operating power applied significantly influences the contaminant removal kinetics and the moisture content in soil has a major effect on the final temperature reachable during MW heating. The first-order kinetic model showed an excellent correlation (r2 > 0.976) with the experimental data for residual concentration at all operating powers and for all soil moistures tested. Excellent contaminant removal values up to 94.8% were observed for wet soils at power higher than 600 W for heating duration longer than 30 min. The use of MW heating with respect to a conventional ex situ thermal desorption treatment could significantly decrease the energy consumption needed for the removal of hydrocarbon contaminants from soils. Therefore, the MW treatment could represent a suitable cost-effective alternative to the conventional thermal treatment for the remediation of hydrocarbon-polluted soil.

Bioavailability and Bioremediation of Diesel Fuel-Contaminated Soil Using Organic Wastes as Supplement

Soil and surface water contamination by organic compounds is a common occurrence in most developing countries. This caused harmful effects on the environment and human beings. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 10% (w/w) diesel fuel amended with 10% soy cake (SC), potato skin (PS) and tea leaf (TL) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (88%) was recorded in soil contaminated with 5% diesel fuel and amended with SC, while only 75% of oil biodegradation was recorded in soil contaminated with 10% diesel fuel and amended with SC. Bioavailability which was assessed by the hydroxypropyl cyclodextrin (HPCD) extraction method showed that bioavailability reduced in soil amended with organic wastes. Results of first order kinetic model to determine the rate of biodegradation of diesel fuel revealed that soil amended with SC recorded the highest kinetic rate of oil biodegradation 0.148 day and 0.103 day in 5% and 10% oil pollution. The results of this study demonstrated the potential of SC as a good substrate to enhance remediation of hydrocarbon contaminated soil at low pollution concentration.

Effect of Soil Texture on Remediation of Hydrocarbons-Contaminated Soil at El-Minia District, Upper Egypt

Soils polluted by waste lubricant oils may affect the hydrosphere compromising the quality of drinking water resources and threatening the aquatic ecosystems. The objective of this study focused to remove waste-lubricant oils from different polluted sites in El-Minia governorate. In this respect some samples were collected from four different industrial sites and identified as sand, loamy sand, clay loam and loam. Then the field conditions were simulates using two experimental models packed with contaminated soil. The remediation processes carried out in both models using surfactant enhanced by air injection then by water washing. The parameters such as soil type, soil heterogeneity, time and washing process was investigated. The results indicated that the high efficiency of oil removal is obtained from sand where the clay loam gives the worst results. The results also reveal that, the high flushing and washing duration time can be attributed to the high percentage of mud in some sites over other sites. This means that the performance of surfactant flushing/water washing can be adversely affected by geologic heterogeneity. Finally, it’s suitable to use pressurized liquid technologies in heterogeneous media, but cleanup times will be longer and more difficult than for the other similar homogeneous media.

Biodegradation of Used Motor Oil in Soil Using Organic Waste Amendments

Soil and surface water contamination by used lubricating oil is a common occurrence in most developing countries. This has been shown to have harmful effects on the environment and human beings at large. Bioremediation can be an alternative green technology for remediation of such hydrocarbon-contaminated soil. Bioremediation of soil contaminated with 5% and 15% (w/w) used lubricating oil and amended with 10% brewery spent grain (BSG), banana skin (BS), and spent mushroom compost (SMC) was studied for a period of 84 days, under laboratory condition. At the end of 84 days, the highest percentage of oil biodegradation (92%) was recorded in soil contaminated with 5% used lubricating oil and amended with BSG, while only 55% of oil biodegradation was recorded in soil contaminated with 15% used lubricating oil and amended with BSG. Results of first-order kinetic model to determine the rate of biodegradation of used lubricating oil revealed that soil amended with BSG recorded the highest rate of oil biodegradation (0.4361 day−1) in 5% oil pollution, while BS amended soil recorded the highest rate of oil biodegradation (0.0556 day−1) in 15% oil pollution. The results of this study demonstrated the potential of BSG as a good substrate for enhanced remediation of hydrocarbon contaminated soil at low pollution concentration.

Ecological Remediation of Hydrocarbon Contaminated Soils with Weed Plant

Considerable efforts have been undertaken to accelerate the breakdown of existing anthropogenic petroleum hydrocarbons (PHCs) by appropriate in situ remediation technologies. In situ phytoremediation, using higher plants to remove, stabilize, degrade, and/or metabolize hazardous contaminants, has emerged as a promising green technology for cleaning up environments contaminated with PHCs. Weed plants are generally considered to have great potential for use in phytoremediation due to their extensive fibrous root systems and relatively robust characteristics, thus helping establish a strong rhizosphere through contaminated soils. In this review, some important mechanisms involved in phytoremedation of PHC contaminated soils, including phytoaccumulation, phytostabilization, phytodegradation, phytovolatilization, and rhizodegradation, were summarized and discussed. In recent years, a large number of laboratory approaches have been developed to further enhance the phytoremediation efficiency of PHC contaminated soils. The success of these laboratory studies has encouraged researchers to attempt phytoremediation of PHC contaminated soils in the field. However, many limitations still exist in order to successfully apply laboratory experiments to trials in the field.

An Investigation of the Ability of a 14C-Labeled Hydrocarbon Mineralization Test to Predict Bioremediation of Soils Contaminated with Petroleum Hydrocarbons

ABSTRACT Bioremediation is a widely accepted technology for the remediation of hydrocarbon-contaminated soil. Treatability studies are usually carried out to assess the biodegradation potential of the contaminants and to design optimal treatments. Laboratory studies measuring soil respiration are often used. One method consists of monitoring the mineralization of a 14C-labeled hydrocarbon surrogate added to the contaminated soil. This study investigates the ability of this method to properly predict the removal of the hydrocarbon contaminants initially found in soils. Mineralization of 14C-labeled hexadecane was monitored in seven soils contaminated with various hydrocarbon mixtures, both fresh and weathered, in microcosm experiments. Reduction of total petroleum hydrocarbon (TPH) concentrations was measured simultaneously in separate microcosms. Both types of microcosms were subjected to the same amendment regimes. For all soils, poor correlation was observed between the mineralization and TPH reduction data sets. Mineralization data supported contaminants removal data in only one soil. Findings indicate that the radioactive surrogate method does not reliably predict the extent of, and the effect of amendments on, the removal of the hydrocarbons initially present in soil, and may therefore predict suboptimal treatment regimes. Recommendations for soil treatability protocols are provided.