Diesel Oil Removal Research Articles

Optimisation of Diesel Polluted Soil Using Response Surface Methodology

This research is based on the investigation of the bioremediation of diesel polluted soil using biostimulation strategy. The study was carried out on a diesel contaminated soil and concentrations: Tween 80 (5-15ml), Poultry droppings (20-60g), Hydrogen Peroxide (0.5-1.5ml) were added and incubated for 28 days of remediation period. Response Surface Methodology with Box-Behnken Design (BBD) was used with three factors and three levels of Tween 80, Poultry droppings and Hydrogen Peroxide as independent variables while diesel oil (Total Petroleum Hydrocarbon) removal was the dependent variable (response). The result showed disparities in the diesel oil biodegradation pattern with respect to Tween 80, Poultry droppings and Hydrogen Peroxide. The statistical analysis, via ANOVA showed coefficient of determination R2 to be 99.89% and P < 0.05. The predicted optimum parameter of Tween 80: 10.10ml, Poultry droppings: 41.46g and Hydrogen Peroxide: 1.10ml were gotten while 56.565% was gotten as the optimal diesel oil removal. At this optimum condition, the observed diesel oil removal was found to be 56.568%. It can be concluded that bioremediation of diesel-contaminated soil resulted in petroleum hydrocarbon degradation.

BIODEGRADATION OF DIESEL OIL IN SOIL AND ITS ENHANCEMENT BY APPLICATION OF BIOVENTING AND AMENDMENT WITH BREWERY WASTE EFFLUENTS AS BIOSTIMULATION-BIOAUGMENTATION AGENTS

The purpose of this study is to investigate and evaluate the effects of natural bioattenuation, bioventing, and brewery waste effluents amendment as biostimulation-bioaugmentation agent on biodegradation of diesel oil in unsaturated soil. A microcosm system was constructed consisting of five plastic buckets containing 1 kg of soil, artificially contaminated or spiked with 10% w/w of diesel oil. Biodegradation was monitored over 28 days by determining the total petroleum hydrocarbon content of the soil and total hydrocarbon degrading bacteria. The results showed that combination of brewery waste effluents amendment and bioventing technique was the most effective, reaching up to 91.5% of diesel removal from contaminated soil; with the brewery waste effluents amendment (biostimulation-bioaugmentation), the percentage of diesel oil removal was 78.7%; with bioventing, diesel oil percentage degradation was 61.7% and the natural bioattenuation technique resulted in diesel oil removal percentage be not higher than 40%. Also, the total hydrocarbon-degrading bacteria (THDB) count in all the treatments increased throughout the remediation period. The highest bacterial growth was observed for combined brewery waste effluents amendment with bioventing treatment strategy. A firstorder kinetic model was fitted to the biodegradation data to evaluate the biodegradation rate and the corresponding half-life time was estimated. The model revealed that diesel oil contaminated-soil microcosms under combined brewery waste effluents amendment with bioventing treatment strategy had higher biodegradation rate constants, k as well as lower half-life times, t1/2 than other remediation systems. This study showed that the microbial consortium, organic solids, nitrogen and phosphorus present in the brewery waste effluents proved to be efficient as potential biostimulation-bioaugmentation agents for bioremediation processes of soils contaminated with diesel oil.

Rhizosphere as a tool to introduce a soil-isolated hydrocarbon-degrading bacterial consortium into a wetland environment

An attempt to incorporate a soil-isolated bacterial consortium capable of degrading hydrocarbons into the sweet flag rhizosphere was made in order to introduce the plant-bacteria combination into a wetland environment. The colonization of the rhizosphere occurred after a diesel oil degradation trial, where the plant was inoculated with the bacterial consortium. Both plant and bacterial growth were monitored. The 16S rRNA gene sequences method was used to verify the presence of the soil-isolates in the plants internal tissues and TTC-dehydrogenase measurements were employed to assess the microbial activity. The incorporation of bacterial cells into the sweet flag rhizosphere resulted in an increased diesel oil removal efficiency (by 50%) and enhanced bacterial and plant growth. Afterwards, the colonized sweet flag rhizomes were planted within a lake shoreline to evaluate the long-term prevalence of microorganisms in the natural environment. The bacterial DNA of the oil-degrading consortium species was detected in the harvested plants even after 8 months.

Removal of Diesel Oil from Soil Using Rhamnolipid and Sodium Dodecyl Sulfonate

The removal of No. 0 diesel oil from two kinds of soils artificially by natural rhamnolipid and synthetic sodium dodecyl sulfonate (SDS) were performed in a batch of soil washing studies. Results showed that both surfactants could remove significant amount of diesel oil from the contaminated soil at different solution concentrations compared with water alone. The maximum removal was obtained at surfactant concentrations below or equal to the critical micelle concentration (CMC). At surfactant concentrations higher than the CMC, removal of diesel oil did not increase further. SDS remained more in solution than rhamnolipid, thus, it was expected to be more effective than rhamnolipid to remove diesel oil. However, the next washing experiment showed that rhamnolipid had more considerable ability in removing diesel oil.

Study on the Removal of Naphthenic Acid From Diesel Oil by Salt Under Supersonic Strengthening

The naphthenic acid in diesel oil was removed by sodium carbonate as deacidification agent under strengthening of supersonic. The influence of affect factors about treating conditions on the acid removal of diesel oil was investigated, such as ultrasonic frequency, volume ratio of sodium carbonate solution to oil (VRSO), ultrasonic work function, and ultrasonic strengthening time. Orthogonal tests were done to confirm the optimum process condition. The results showed that the optimum condition was that ultrasonic frequency was 28 KHz, VRSO was 0.30, ultrasonic work function was 350 W, and ultrasonic strengthening time was 6 min. Under this optimum condition, acidity of diesel oil was reduced to 4.88 mgKOH/100 mL from 135.52 mgKOH/100 mL, and deacidification rate of naphthenic acid reached 96.4%.

Diesel oil removal by immobilized Pseudoxanthomonas sp. RN402

Pseudoxanthomonas sp. RN402 was capable of degrading diesel, crude oil, n-tetradecane and n-hexadecane. The RN402 cells were immobilized on the surface of high-density polyethylene plastic pellets at a maximum cell density of 10(8) most probable number (MPN)g(-1) of plastic pellets. The immobilized cells not only showed a higher efficacy of diesel oil removal than free cells but could also degrade higher concentrations of diesel oil. The rate of diesel oil removal by immobilized RN402 cells in liquid culture was 1,050mgl(-1)day(-1). Moreover, the immobilized cells could maintain high efficacy and viability throughout 70 cycles of bioremedial treatment of diesel-contaminated water. The stability of diesel oil degradation in the immobilized cells resulted from the ability of living RN402 cells to attach to material surfaces by biofilm formation, as was shown by CLSM imaging. These characteristics of the immobilized RN402 cells, including high degradative efficacy, stability and flotation, make them suitable for the purpose of continuous wastewater bioremediation.

A Study on Removing Naphthenic Acid From Diesel Oil by Salt

Sodium carbonate as deacidification agent was used to remove naphthenic acid from diesel oil. The influence of affect factors about treating conditions on the acid removal of diesel oil was investigated, such as volume ratio of deacidification agent-to-oil (VRDO), reaction temperature, stirring time, and resting time. Orthogonal tests were done to conform the optimum process condition. The results showed that the optimum condition is that VRDO was 0.40, reaction temperature was 330 K, stirring time was 6 min, and resting time was 35 min. Under the optimum condition, acidity of diesel oil was reduced to 5.15 mgKOH/100 mL from 135.52 mgKOH/100 mL, and if deacidification rate of naphthenic acid reached 96.8%, diesel oil recovery could reach 92.6%. The quality index of diesel met the national standard.

Study on Influencing Factors on Removal of Diesel Oil from Unsaturated Zone by Soil Vapor Extraction

This paper deals with the influencing factors on removal of diesel oil from by soil vapor extraction (SVE) method. A series of one-dimensional column experiments were conducted to study the influencing factors for SVE method, the factors included extracted vapor flow rate,water content and the concentration of the contaminant. The results indicated that: (1) the increase of vapor flow rate led to higher contaminant removal efficiency,but the increment of removal was not significant at higher flow rate levels;(2) the moisture content is 12% coarse sand elimination rate is bigger than 1% coarse sand;(3) the soil index of oil is higher, the extraction time to be longer, it is not suitable processes with SVE that the diesel oil density is excessively low.

Uptake of Hydrocarbon by Pseudomonas fluorescens (P1) and Pseudomonas putida (K1) Strains in the Presence of Surfactants: A Cell Surface Modification

The objective of this research was the evaluation of the effects of exogenous added surfactants on hydrocarbon biodegradation and on cell surface properties. Crude oil hydrocarbons are often difficult to remove from the environment because of their insolubility in water. The addition of surfactants enhances the removal of hydrocarbons by raising the solubility of these compounds. These surfactants cause them to become more vulnerable to degradation, thereby facilitating transportation across the cell membrane. The obtained results showed that the microorganism consortia of bacteria are useful biological agents within environmental bioremediation. The most effective amongst all, as regards biodegradation, were the consortia of Pseudomonas spp. and Bacillus spp. strains. The results indicated that the natural surfactants (rhamnolipides and saponins) are more effective surfactants in hydrocarbon biodegradation as compared to Triton X-100. The addition of natural surfactants enhanced the removal of hydrocarbon and diesel oil from the environment. Very promising was the use of saponins as a surfactant in hydrocarbon biodegradation. This surfactant significantly increases the organic compound biodegradation. In the case of those surfactants that could be easily adsorbed on cells of strains (e.g., rhamnolipides), a change of hydrophobicity to ca. 30–40% was noted. As the final result, an increase in hydrocarbon biodegradation was observed.

Physical and Biological Treatment of Oil-Contaminated Soil in a Baffled Roller Bioreactor

ABSTRACT Physical and biological removal of diesel oil from contaminated soil was studied in a baffled roller bioreactor. Initially, the effects of four factors (soil loading, temperature, pH, and surfactant) on physical removal of diesel oil were investigated. Only the presence of a surfactant (sodium dodecyl sulfate [SDS]) demonstrated a significant effect on diesel oil removal. Diesel oil removal efficiency was increased from 32.0% to 63.9% in the presence of 100 mg/L SDS. Using a microbial culture enriched from contaminated soil, biological treatment of diesel oil polluted soil under different soil loadings (15% to 50%), different diesel oil concentrations (1 to 50 g/L), and different types of soil (sand, silt, and clay) was then investigated in the baffled roller bioreactor. Biodegradation consisted of both fast and slow stages for degradation of light and heavy compounds, respectively. All biodegradation experiments demonstrated significant decreases in diesel oil concentrations (88.3% in 14 days for initial diesel oil concentrations of 1000 mg/L and a wide range of soil loadings). The presence of silty or sandy soils enhanced the biodegradation rate compared to the control bioreactor (without soil). The sandy soil loading had no effect on the biodegradation results. Using the enriched culture, the baffled roller bioreactor was able to biodegrade high diesel concentrations (up to 50 g/L) with biodegradation rates of 112.2 and 39.3 mg/L· h during fast and slow stages, respectively.

Electrokinetic Remediation of Soil Contaminated with Diesel Oil Using EDTA–Cosolvent Solutions

The effect of a chelating agent (EDTA), cosolvent (n-propanol), and non-ionic surfactants (Tergitol 15-S-7 and Tergitol NP-10) as additives in the purging solution for electrokinetic remediation of soil contaminated with diesel oil was investigated. It was found that EDTA functioned as both an electrolyte and a desorbent for hydrophobic organic contaminants. Addition of surfactant with EDTA was not effective for diesel oil transport and removal. The addition of n-propanol and EDTA enhanced hydrocarbon removal efficiency, especially for aromatic hydrocarbons. There was no significant enhancement of removal by use of a combination of EDTA, surfactant and n-propanol relative to the use of EDTA and n-propanol together.

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions II: Continuous Mode of Operation

The objective of this study was to investigate the relationship between interfacial tension (IFT) and foam characteristics and the efficiency of diesel oil removal from water in a continuous froth flotation column. The effects of operational parameters, including surfactant concentration, salinity, oil-to-water ratio, foam height, air flow rate, and hydraulic retention time (HRT) on the oil removal were investigated in the continuous mode of a froth flotation operation and compared to batch operation results. Unlike the batch system, for the continuous system used in the present study, having only branched alcohol propoxylate sulfate sodium salt surfactant (C14–15(PO)5SO4Na) and NaCl present in the solution yielded such poor foam characteristics that a stable froth which overflowed the flotation column could not be produced, so the addition of sodium dodecyl sulfate (SDS) as a froth promoter was used to improve the foam stability. Unlike the batch froth flotation system with only C14–15(PO)5SO4Na, the continuous froth flotation with the mixture of C14–15(PO)5SO4Na and SDS, it was not possible to find a SDS and a NaCl concentration at which both ultralow IFT and good foaming were both achieved. Foam formation, stability, and production rate were found to be crucial parameters to the froth flotation efficiency. The continuous froth flotation system offers a high diesel oil removal of 96% in the single stage unit. Demonstration of efficient operation in the continuous mode in this work is important to the practical application of froth flotation in large scale processing.

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions I: Foam Characteristics, and Equilibration Time

Froth flotation is a surfactant‐based separation process which is suitable for treating dilute wastewaters. To achieve high performance for the froth flotation operation, the combination of an ultra‐low interfacial tension (IFT) between excess oil and excess water phases, high foam production rates, and high stability of the foam produced, must be attained. To obtain the ultra‐low interfacial tensions, a Winsor Type III or middle phase microemulsion has to be formed. In this study, branched alcohol propoxylate sulfate sodium salt with 14–15 carbon number and 4 PO groups (Alfoterra 145–4PO) was used to form microemulsions with diesel oil. From the results of this work, an increase in surfactant concentration decreased the IFT, and increased foam stability. To obtain the minimum IFT in the region of a Winsor Type III microemulsion, the addition of 5 wt.% NaCl was needed. However, this optimum salinity does not result in effective froth flotation due to poor foam characteristics. The results indicate that both the IFT and the foam characteristics should be optimized to achieve high efficiency of oil removal in a froth flotation operation. Unlike the previously‐studied ethylbenzene system, agitation of the solution before introduction into the flotation column yielded the lowest diesel oil removal efficiency because of the poor foam characteristics compared to either unagitated systems or systems allowed to equilibrate for one month.

Diesel oil removal from water by froth flotation under low interfacial tension and colloidal gas aphron conditions

The objective of this work was to investigate the relationship between the froth characteristics, the system interfacial tension (IFT), and the efficiency of diesel oil removal by froth flotation under colloidal gas aphron (CGA) conditions. Branched alcohol propoxylate sulfate sodium salt (C 14–15(PO) 5SO 4Na) as an extended surfactant, was used to form CGA and microemulsions with diesel oil. For the CGA studies, the effects of salinity, surfactant concentration, stirring speed, and stirring time were investigated in order to determine the optimum conditions of the CGA formation which were further used for the froth flotation experiments. The air bubble size measurement was carried out in order to correlate the air bubble size to the froth flotation performance. The results showed that the use of CGA enhanced the process performance of froth flotation in terms of both the removal and the enrichment ratio of diesel oil since CGA increased both froth formation and stability. The froth flotation column which was operated at an air flow rate of 0.30 l/min with the feed solution prepared under non-equilibrium and the CGA conditions at 0.1 wt.% C 14–15(PO) 5SO 4Na, 3 wt.% NaCl, with a stirring speed of 5000 rpm and a stirring time of 5 min, gave the highest oil removal of 97%.

Treatment of diesel fuel contaminated soil in jet–fluidized bed

Bioremediation of diesel-oil contaminated soil (4 wt%) was studied in a jet–fluidized reactor by the stimulation of indigenous oil micro-organisms. The experiments were carried out using different rates of aeration and/or jet air flow and consequently various mixing rates to investigate their influence on biodegradation and removal ratios. The diesel-oil content decreased rapidly in all experiments in the first 7 days, with different removal ratios. The presence of the jet favoured inter-particle exchanges, transfers between the various phases involved, and accelerated the diesel-oil removal process. Also, the influence of aeration seemed negligible compared with that of the jet. Removal and biodegradation ratios ranged from 69% to 99%, and 54% to 84%, respectively after 15 days of treatment. The best biodegradation ratio of 84% occurred in the case of an expanded bed with minimum fluidization, operating at a jet velocity of 37 m/s. The diesel-oil biodegradation was governed by first-order kinetics. Important air flows enhanced the efficiency of diesel-oil removal, and abiotic loss and hence decreased the biodegradation ratio.

Removal by Sorption andIn SituBiodegradation of Oil Spills Limits Damage to Marine Biota: A Laboratory Simulation

This study examined the efficiency of cotton grass fibers in removing diesel oil from the surface of water in conditions prevailing in the Baltic Sea. The effect of low temperature, salinity, and bacterial amendments were tested in laboratory-scale set-ups, whereas 600-L mesocosms filled with Baltic Sea water were used for testing the effects of diesel oil and rapid removal of the oil on microorganisms, phytoplankton, and mussels. Cotton grass proved to be an excellent sorbent for diesel oil from the water surface at a low temperature. Inoculation with diesel-enriched microorganisms enhanced degradation of oil significantly in laboratory-scale experiments. In mesocosm experiments, the addition of diesel oil (0.66 mg L(-1), 0.533 L m(-2)) to the basins resulted in higher microbial density than in all other basins, including inoculated ones, suggesting that the Baltic Sea contains indigenous hydrocarbon degraders. The removal of oil with cotton grass significantly improved the survival of mussels in the mesocosm tests: 100% mortality in diesel basins versus 0% mortality in basins with cotton grass, respectively. However, the surviving mussels suffered from histopathological changes such as inflammatory responses, degenerations, and cell death. The observed rescuing effect was observable even when the cotton grass-bound oil was left in the water. The results underline the importance of rapid action in limiting damage caused by oil spills.

Impacts of soil microbial and fungal biomasses on bioremediation of diesel oil in soil microcosms

A study of changes in microbial biomass during the decontamination of diesel oil was conducted in five microcosms (M1–M5). The rate of removal of diesel oil varied as follows: M2 (fertilized) 35.63% > M3 (penicillin–streptomycin treatment) 33.0% > M4 (cycloheximide treatment) 31.33% > M5 (treatment with a mixture of antibiotics) 23.4% > M1 (the control treatment, where a poison was applied) 14.5%. The fungal count, ergosterol content, biomass C and CO 2 efflux were all measured. All of these properties increased gradually in the M2, M3 and M5 samples, and decreased after the beginning of the experiment in the M1 and M4 microcosms. Seventeen fungal species were isolated during 105 days of incubation. Species present in abundance were: A. flavus, A. niger, A. flavipes and P. chrysogenum, all of which were high in biomass (33.0, 25.3, 5.0 and 22.7 mg dry weight) and ergosterol content (31.5, 49.3, 19.0 and 23.4 mg/g dry weight) respectively. On average, the ergosterol to microbial biomass ratio was 0.004 in the M2 and M3 microcosms. A significant correlation between ergosterol and microbial biomass C, and microbial biomass C and CO 2 was observed. Selective inhibition methods indicated that both fungal and bacterial respiration increased evenly for three months and then abruptly decreased. The fungal activity is higher than the bacterial activity, as indicated by the highest fungal to bacterial ratio (2.04).

Performance and mechanism of a hydrophobic–oleophilic kapok filter for oil/water separation

Abstract A natural vegetable fiber, kapok, was evaluated for its feasibility as filter material for separating immiscible liquids such as oil/water mixtures. Two types of oils, namely diesel and hydraulic, were investigated. Various simulated oily waters were prepared by mixing tap water with one of these oils to produce binary oil/water mixtures of varying oil percentages, such as 5%, 10% and 15% by weight. The effect of filter packing density on the dynamics of oil/water separation during the filtration process and the filtrate quality were investigated. Due to the hydrophobic–oleophilic surface characteristic of the kapok fiber, water could be filtered through the filter while oils were retained, causing separation of oil from water. The filtration efficiency for removal of diesel and hydraulic oil from their respective oily waters reached 100% and more than 99.4%, respectively, which showed an excellent performance of kapok in removing oils from oily waters. The hydraulic conductivity of the kapok filter was found to decrease with the advance of the oil front. The filtration rate of both types of oily waters decreased with increasing filter packing densities and influent oil contents. The kapok filter performed equally well in terms of total filtrate collected before breakthrough for the two different oils, albeit the filtrate rate could be viscosity dependent. A packing density of 0.07 g/cm 3 was the optimum one for diesel and hydraulic oil removal. At breakthrough, the oil/water/air three-phase partition within the filter bed is a function of influent oil concentration, oil type, and packing density of the filter.

EVALUATION OF BIOSTIMULATION, BIOAUGMENTATION AND USE OF BIOSURFACTANT AS TREATMENT TECHNIQUE OF CLAY SOIL CONTAMINATED WITH DIESEL OIL

The aim of the present work was to evaluate the use of biosurfactant (rhamnolipid) in the biodegradation of diesel oil in clay soils. The assays were held in with an aerobic fixed bed reactor with 400g of oil-contaminated soil, at room temperature and aeration rate of 3L/h. To evaluate the techniques of biostimulation, bioaugmentation and the use of biosurfactant in the removal of diesel oil, different conditions was evaluated. Total petroleum hydrocarbon (TPH) content was measured in order to monitor the diesel oil biodegradation and total heterotrophic (BHT) and hydrocarbon-degrading bacteria (BHc) were enumerated, in the beginning and at the end of 30 days of experiments. The TPH removal was above 50% when fertilizer and/or biosurfactant were used. The addition of fertilizer was the relevant factor in the improvement of biodegradation of diesel oil.

Remediation of a Diesel Contaminated, Sandy-Loam Soil Using Low Concentrated Surfactant Solutions (5 pp)

Surfactant enhanced ex-situ soil washing can be used to remediate diesel contaminated soils. Surfactants enhance the diesel removal from soils by two processes: mobilization and solubilization. Mobilization occurs at surfactant concentrations below the critical micelle concentration (CMC), while solubilization occurs at surfactant concentrations beyond the CMC of the surfactant. In this paper, the leaching of diesel from a self contaminated (10 000 mg diesel/kg) sandy-loam soil was studied using low concentrated non-ionic surfactant solutions of Tergitol NP-10 (10-6 to 10-3 mol/L). The surface tension of the supernatant solutions of soil suspensions in non-ionic surfactant (Tergitol NP-10) solutions (10-6 to 10-3 mol/L) was measured to determine the total surfactant concentration (surfactant sorbed onto the soil + surfactant in solution) at which micelles are present in the water phase of the soil suspension, or 'effective critical micelle concentration' (ECMC), and to calculate the sub-CMC sorption isotherm of Tergitol NP-10 onto the soil. The diesel removal was measured by soil leaching experiments with Tergitol solutions ranging from 10-6 to 10-3 mol/L. The sub-CMC sorption isotherm of Tergitol onto the soil could be described by the Freundlich equation. Even at very low surfactant concentrations (10-6 mol/L) the surfactant enhanced the diesel removal from the soil. Up to the surfactants' ECMC the diesel removal increased in a linear way with an increasing surfactant concentration in the wash water. A significant part (20%) of the diesel oil was removed in the presence of surfactant, but in absence of micelles. Beyond the surfactants' ECMC, the increase in diesel removal efficiency with increasing surfactant concentration was less pronounced. When the added surfactant concentration was increased to 10-3 mol/L, which corresponds to an equilibrium surfactant concentration in the supernatant solution (6.77.10-4 mol/L) above the CMC, the diesel oil removal was increased up to 50%. At this surfactant concentration emulsion formation was observed. Surfactant aided leaching of diesel from a self-contaminated, sandy-loam soil with surfactant solutions below their ECMC was able to remove in one step 20% of diesel from the soil by the mobilization mechanism. Succesive treatments or continuous leaching with surfactant solutions below their ECMC was not studied but is likely to reduce the diesel contamination further and at the same time avoid problems with emulsion formation.