Diesel Oil Concentration Research Articles

A Quantitative and Qualitative Analysis of the Lubricity of Used Lubricating Oil Diluted with Diesel Oil

Experience shows that dilution of lubricating oil with diesel oil is unfavorable to the engine, causing issues including deterioration of engine performance, shortening of oil life, and reduction in engine reliability and safety. This paper presents the verification of the hypothesis that the changes in lubricity, friction coefficient, and decreasing oil film thickness (using a relative approach, given as a percentage) are similar for lubricating oil and diesel mixtures prepared from fresh lubricating oil and used lubricating oil. To validate this hypothesis, an experiment is conducted using a high-frequency reciprocating rig (HFFR), in which the lubricity is determined by the corrected average wear scar WS1.4, the coefficient of friction μ, and the percentage relative decrease in oil film thickness r. A qualitative visual assessment of the wear scars on the test specimens is also performed after the HFFR tests. The testing covers mixtures of SAE 30 grade Marinol CB-30 RG1230 lubricating oil with Orlen Efecta Diesel Biodiesel. The used lubricating oil is extracted from the circulating lubrication system of a supercharged, trunk-piston, four-stroke ZUT Zgoda Sulzer 5 BAH 22 engine installed in the laboratory of ship power plants of the Maritime University of Szczecin. Mixtures for the experiment are prepared for fresh lubricating oil with diesel oil and used lubricating oil with diesel oil. Mixtures of these lubricating oils with diesel oil are examined for diesel oil concentrations in the mixture equal to 1, 2, 5, 10, 15, and 20% m/m. The results of the experiment confirm the hypothesis, proving that, for up to 20% m/m diesel oil concentration in lubricating oil, the changes in the lubricity of used lubricating oil diluted with diesel oil can be evaluated based on reference data prepared for mixtures of diesel oil with fresh lubricating oil. The linear approximation of μ and r trends is made with a certain margin of error we estimated. The experiment also confirms the results of previous studies which state that oil aging products in small quantities contribute to improved lubricity.

Modeling of Selected Parameters of Used Lubricating Oil Diluted with Diesel Oil Using the Characteristics of Fresh Lubricating Oil

This article presents the verification of the hypothesis on using certain approximation curves in the evaluation of used lubricating oil. These curves are plotted for fresh lubricating oil to approximate the parameters of lubricating oil diluted with diesel oil. To confirm the hypothesis, an experiment is conducted to determine the flash point, initial boiling point, density at 15 °C, kinematic viscosity at 40 °C and 100 °C, and viscosity index. The analysis covers fresh oil and used SAE 30 grade Marinol CB-30 RG1230 oil taken from the circulating lubrication system of a supercharged, trunk-piston, 4-stroke ZUT Zgoda Sulzer 5 BAH 22 engine that is located in the Marine Power Plant Laboratory of the Maritime University of Szczecin. Undiluted lubricating oils (both fresh and used) and mixtures of lubricating oils with diesel oil are examined for diesel oil concentrations in the mixture equal to 1, 2, 5, 10, 15, and 20% m/m. Orlen Efecta Diesel Biodiesel is used to prepare the mixtures. The functions approximating the parameters for fresh oil are determined and adapted to describe the variation of the same parameters for the used lubricating oil. For each case, the coefficient of determination, the maximum relative error of the model fitting to the experimental results, and the root mean square error (RMSE) are determined. In the experiment, the variation in the parameters of the used lubricating oil remained the same as for fresh oil parameters. Thus, the research hypothesis is confirmed.

Arrhenius Equation for Calculating Viscosity in Assessing the Dilution Level of Lubricating Oil with Diesel Oil—A Case Study of SAE 30 and SAE 40 Grade Marine Lubricating Oils

This article proposes using the Arrhenius model for estimating the viscosity of a mixture of two liquids in the quantitative assessment of the physicochemical properties of lubricating oils in the context of assessing the level of dilution of lubricating oil with diesel oil. Dynamic are made of mixtures of lubricating oil and diesel oil with known concentrations of 0, 1, 2, 5, 10, 20, 50, and 100% m/m of the diesel oil content in the mixture. Mixtures of the most popular oils (viscosity classes SAE 30 and SAE 40) with diesel oil that meet the requirements of the DMX of the marine distillate fuels category are prepared and tested. Viscosity measurements are performed at 40, 50, 60, 70, 80, 90, and 100 °C temperatures. The Arrhenius model is used to estimate the viscosity of the mixtures with an assumed diesel oil content and to estimate the diesel oil concentration in the mixtures with a known measured viscosity value. In both cases, the absolute estimation error is determined, and the accuracy of the estimation is assessed against the known concentration of diesel oil in the mixture with lubricating oil and the temperature at which the viscosity is measured. The estimated concentrations of diesel oil in mixtures with lubricating oil are useful to assess the condition of the lubricating oil (for concentrations of diesel oil lower than 5% m/m). The method is proposed to be used in practice to support standard laboratory oil analysis.

Bioremediation of diesel oil: potential use of bacteria consortium Lactobacillus fermentum and Clostridium beijerinckii in degrading Total Petroleum Hydrocarbon (TPH)

Diesel oil is a major petroleum-refined product known as the primary environmental pollutant due to its toxic complex hydrocarbons and difficulty in decomposing naturally. This study aims to determine the efficiency of TPH (Total Petroleum Hydrocarbon) removal in the bioremediation process of diesel oil pollution by utilizing a bacteria consortium of Lactobacillus fermentum and Clostridium beijerinckii as biocatalysts. The diesel oil degradation test was conducted on a laboratory scale using Stone Mineral Salt Solution (SMSs) liquid media with a batch system (limited culture). The temperature was set at 30°C with a rotation speed of 150 rpm for 10 days. Different treatments of pH (5, 7, 9) and contact time (10, 20, 30 days) were applied to varied diesel oil concentrations (5, 10, 20%, v/v). The oil components were measured using Gas Chromatography-Flame Ionization Detector. Diesel oil samples were put into SMSs containing 10% bacterial consortium and 10% NPK fertilizer. The sensitivity test showed that the bacterial consortium was resistant, proven by the absence of an inhibition zone around the disc paper area containing diesel oil. The highest TPH removal efficiency found was 97.3% when 5% diesel oil was degraded by the bacterial consortium at pH 7 for 20 days. This study proves that the bacterial consortium can be recommended in bioremediation to alleviate diesel oil pollution in the environment.

Assessment of the Impact of Lubricating Oil Contamination by Biodiesel on Trunk Piston Engine Reliability

The rheological, ignition, and tribological properties of lubricating oils diluted with biodiesel were analyzed. The flash point tFP, calculated cetane index CCI, density ρ, coefficient of the temperature density change ε, kinematic viscosity ν, dynamic viscosity η, viscosity index VI, and lubricity during a High-Frequency Reciprocating Rig (HFFR) test (x, y, WSD, and WS1.4) and lubricating conditions during an HFFR test (oil film resistance FILM and friction coefficient μ) were determined. The test was performed for the oil mixtures of the lubricating oil of the SAE 30 and SAE 40 viscosity grades, which were diluted with the biodiesel blend (D93B7—diesel oil with 7% v/v fatty acid methyl esters, FAME) at concentrations of diesel oil in the mixture equal to 0% (pure lubricating oil), 1%, 2%, 5%, 10%, 20%, 30%, 50%, and 75% m/m, respectively. The experiment confirmed the existence of clear relationships between the increase in the dilution of lubricating oil with tested biodiesel blend and tFP, ρ, ε, ν, η, and VI, and the deterioration of lubrication conditions. It is recommended to take remedial action even in the case of low diesel oil concentration (<5% m/m) in the lubricating oil due to tFP, ν, and η changes. Simultaneously, the tests showed no significant effect on the lubricity and the CCI. The critical contamination of oil with fuel in the range of 2–5% by weight, as indicated in the literature, still allowed for a certain “safety margin” regarding these parameters. However, when the concentration of diesel fuel in the lubricating oil exceeded 5–8% m/m, the deterioration of the lubrication was expressed by a decrease in FILM and an increase in μ was observed; hence, such a contamination should be considered excessive. When the concentration of diesel fuel exceeds 10% by weight, there is a serious risk of engine damage during operation.

Contrasting Responses and Phytoremediation Potential of Two Poplar Species to Combined Strontium and Diesel Oil Stress.

The soil pollution caused by diesel oil and heavy metals has become an increasingly serious environmental issue, with negative global-scale impacts. The remediation of contaminated soil requires special attention, in which phytoremediation has emerged as an ecofriendly solution. However, the response of plants to the combined stress of diesel oil and heavy metals remains largely unknown. In this study, the aim was to investigate the potential of Populus alba and P. russkii for phytoremediation by examining their response to combined diesel oil and heavy metal stress. In a greenhouse experiment using soil contaminated with 15 mg kg-1 of diesel oil and varying concentrations of Sr (0, 10, or 100 mg kg-1), we studied the physiological and biochemical changes, as well as the Sr absorption, of P. alba and P. russkii. The results showed that at high concentrations of Sr and diesel oil, the growth of both species was substantially inhibited, but P. alba exhibited higher resistance due to its higher antioxidant enzyme activities and increased accumulation of soluble sugar and proline. Additionally, P. alba concentrated Sr in the stem, whereas P. russkii accumulated Sr in the leaf, exacerbating its negative effects. Diesel oil treatments were beneficial for Sr extraction due to cross-tolerance. Our findings indicate that P. alba is more suitable for the phytoremediation of Sr contamination due to its superior tolerance to combined stress, and we identified potential biomarkers for monitoring pollution. Therefore, this study provides a theoretical basis and implementation strategy for the remediation of soil contaminated by both heavy metals and diesel oil.

Particles Morphology of Mechanically Generated Oil Mist Mixtures of SAE 40 Grade Lubricating Oil with Diesel Oil in the Context of Explosion Risk in the Crankcase of a Marine Engine

This article presents research results on mechanically generated oil mists. The research was carried out for oil mixtures for the Agip/Eni Cladium 120 SAE 40 API CF oil for industrial and marine engines diluted with diesel oil Orlen Efecta Diesel Bio at diesel oil concentrations of 2%, 5%, 10%, 20%, and 50% m/m. Pure lubricating oil and pure diesel oil were also tested. Droplet size distributions were determined for the reference moment at which residual discrepancies R between the measurement data and the sprayed pure diesel oil calculation model obtained the lowest value. For mechanically generated oil mists, the light transmission coefficient through the oil mist T, the specific surface area of the oil mist SSA, and the volumetric share of drops DV(V%) for 10%, 50%, and 90% of the total volume of the generated oil mist were determined. The span of the volumetric distributions of droplet sizes SPAN, Sauter mean diameter D[3,2], De Brouckere mean diameter D[4,3], the volumetric and mass percentage of droplets with diameters ≤5 μm (diameters necessary for a crankcase explosion), the minimum difference between the measurement results, and the calculation model used by the residual error measuring device were determined. The best fit in each measurement cycle (the smallest R value was analyzed. For specific indicators, correlations with diesel oil levels in the mixture were determined using the Pearson rXY linear correlation coefficient. Those results confirmed an increase in smaller-diameter droplets, an increase in the number of droplets with diameters up to 5 μm, and an increase in the span of the oil mist droplet diameter distribution with additional diesel oil. This confirmed a relationship between an increased lubricating oil dilution and an increased explosion risk in the crankcase.

BIODESULFURISATION OF SOLAR OIL FROM THE CEPU PPSDM OIL AND GAS REFINERY USING Rhodococcus erythropolis BACTERIA

Diesel oil is a type of fuel for diesel engines as a result of processing from crude oil. One of the content of diesel oil that causes various problems is sulfur compounds. Excess sulfur content will cause odors in processed products, the calorific value produced can decrease, causing corrosive properties in processing equipment at the PPSDM Migas refinery such as fractionation columns, refinery storage tanks, distribution pipes, pumps, and vehicle storage tanks. The limit of sulfur content in diesel oil set by the Director General of Oil and Gas is 50 ppm. This study aims to determine the ability of Rhodococcus erythropolis bacteria to biodesulfurize diesel oil, to determine the growth activity of Rhodococcus erythropolis bacteria to biodesulfurize diesel oil, and to determine whether the biodesulfurization process can cause corrosivity in diesel oil. The method used is biodesulfurization of growing cells using Rhodococcus erythropolis bacteria, sulfur testing is done by ASTM D2622 method, and corrosivity testing is done by ASTM D130 method. The treatments used in this study were variations in the pH of the growth medium, variations in the concentration of diesel oil, and variations in the length of incubation time. In this study, the bacteria Rhodococcus erythropolis succeeded in reducing the highest sulfur content in diesel oil from 2167.9 to 1766.1 (ppm) with pH 8 treatment. The biodesulfurization process caused a decrease in the pH of the media from 8.2 to 7.1 with pH treatment. 8.

Flotation response of a bituminous coal sample in presence of a pyrolitic oil recycled from used car tires

ABSTRACT In this research work, the role of a pyrolitic oil (PO) produced by pyrolysis of used car tires in coal flotation was evaluated using an extended full factorial design. Effects of operating parameters including pulp solid content and the concentration of pine oil, diesel oil, and pyrolitic oil on ash content and yield of final concentrate as process responses were assessed using experimental and statistical analyses. Fourier Transform Infrared Spectroscopy (FTIR) technique revealed that PO consists of hydrocarbons and their hydrophilic oxides. Analysis of variance (ANOVA) results indicated that the main effect of all parameters on flotation responses was significant. Experimental results showed that pyrolitic oil increased both the ash content and total yield through a nonlinear trend in ranges of 5% and 40%, respectively. Nonselective interaction between pyrolitic oil and pine oil molecules, and competitive adsorption of PO and diesel oil on the surface of coal particles were found to be the chief reasons behind the observed curved behavior of flotation measures. The negative effect of PO on ash content of final concentrate was also ascribed to the interaction between hydrophilic groups in PO structure and the oxide nature of noncombustible materials in coal particles.

Isolation and Characterization of Biosurfactant Producing Pseudomonas aeruginosa YLA03 and its Diesel Degradation Potentials

This work was aimed at isolating and characterising biosurfactant producing bacteria strain from diesel oil contamination sites. The potential of the strain to degrade diesel oil n-alkanes was further studied. Soil samples were collected from diesel rich areas, and identified strains were grown on minimal media that contained diesel oil as only carbon source. Enrichment culture technique was used to identify bacteria. Seventeen bacteria strains were identified based on their capacity to use diesel oil as carbon source. Other qualitative screening methods were employed to determine the potential to produce biosurfactants. Isolate A03 was the only candidate that shows positive signs for drop collapse, foaming, haemolytic, oil displacement and emulsification tests. The effect of various culture parameters (incubation time, concentration of diesel, nitrogen source, pH and temperature) on biodegradation of diesel was evaluated. Optimum pH was 8.0 at 35° C, while the incubation time at maximum bacteria growth was five (5) days. The favourable diesel oil concentration was 7.5% for the isolate. The isolate has shown degradative ability towards dodecane, Tridecane, tetradecane but was unable to degrade 2, 6, 10-trimethyl- dodecane. It degraded between 10.09% - 45.39% of individual diesel alkanes. The strain has exhibited potential for degrading diesel alkanes and was identified as pseudomonas aeruginosa strain A3 (Accession Number: MZ027605) using the 16S rRNA. Sequencing.

Enhanced remediation of diesel contaminated soil by the combined use of Lolium perenne and bacterial consortium

Rhizoremediation is a cost effective and aesthetically pleasing technology for the remediation of diesel polluted environment. The influence of diesel fuel contamination on Lolium perenne with bacterial consortium (Microbacterium schleiferi and Bacillus subtilis) on plant growth and hydrocarbon degradation was investigated. In this study, three different bacterial strains were grown at varying diesel oil concentration i.e. 0.5%, 1%, 1.5%, 2% and 2.5%. Bacteria were also screened for biosurfactant, indole 3-acetic acid production, phosphate solubilization, and antifungal bioassay. Microbacterium schleiferi and Bacillus subtilis were able to grow at 2% diesel oil concentration and exhibited plant growth promoting activities. Green house analysis revealed that augmentation with biosurfactant producing and plant growth promoting bacteria enhanced the plant growth and diesel oil degradation (80%) as compared to the treatments in which bacteria and plants were separately used. Therefore, the study concludes that application of selected strains with the Lolium perenne is a better approach for successful remediation of diesel oil contaminated soil.

Preparation of Micron-Scale Activated Carbon-Immobilized Bacteria for the Adsorption–Biodegradation of Diesel Oil

This paper investigated the micron-scale activated carbon (MAC) immobilized diesel-oil-degrading bacteria (bio-MAC) used as remediation materials for the removal of diesel-oil-contaminated water. The high-efficiency indigenous diesel-oil-degrading bacteria were firstly screened and enriched, then the MAC was used as a diesel oil sorbent and biocarrier for the immobilization of degrading bacteria to prepare the bio-MAC material. The removal performance of the bio-MAC was evaluated via a comparison with the freely degrading bacteria and MAC. The SEM results demonstrated that the diesel-oil-degrading bacteria were effectively immobilized and grew well on the surfaces of MAC particles. The concentration of MAC significantly influenced the growth and activity (DHA and LPS) of immobilized bacteria, and the MAC addition of 3.0 g/L was proven to be an optimum amount for the preparation of bio-MAC. The high-throughput sequencing analysis further indicated that the bacteria immobilized on MAC showed higher abundance levels and diversities index values compared to freely suspended bacteria, such as Pseudomonas, Rhodococcus, Bacillus and Microbacterium. The FTIR spectroscopy results showed that the bio-MAC could effectively degrade the aliphatic hydrocarbons, alkenes and aromatic compounds of diesel oil to carboxylic acids, esters, alcohols and other metabolites. When the concentration of diesel oil was 1 g/L, the removal efficiency for the diesel oil of bio-MAC reached 86.35% after 15 days, while only 23.82% and 70.97% of the diesel oil was removed using the same amount of free bacteria and MAC, respectively. The prepared bio-MAC showed a synergic effect of adsorption and biodegradation and efficiently removed diesel oil from wastewater.

Electromagnetic Properties Monitoring to Detect Different Biodegradation Kinetics in Hydrocarbon-Contaminated Soil

The electromagnetic properties (electrical permittivity and electrical conductivity) of three different soil mesocosms polluted with diesel oil were monitored using a time-domain reflectometry probe for 8 months. The main target of the research was to establish a relationship between the development of biological activity within the mesocosms and the temporal behaviour of electromagnetic properties. The trend of the electromagnetic properties exhibited different responses that could be related to the composition of the mesocosms and their variation with time during the runs. We considered three different mesocosms with similar soil conditions and the same diesel oil concentration: porosity of 45%, volumetric diesel oil content of 9%, and volumetric water content of 15%. The first one was subjected to a natural attenuation (NA), the second one was biostimulated without inoculation (BS), and the third one was biostimulated with inoculation (BS + IN). The biostimulated mesocosms showed a marked decrease in electrical permittivity and electrical conductivity, whereas the naturally attenuated mesocosm did not show these variations. Between the biostimulated mesocosms, the inoculated one showed the fastest variations in the electromagnetic properties. The microbial activity and the pollutant degradation were evidenced by the analyses performed at the end of the experiment. As demonstrated by the results for the fluorescein diacetate analysis, the microbial activity was a bit higher for the inoculated microcosm, which also showed faster variations of the electromagnetic properties. In the biostimulated mesocosms, the removal of diesel oil was 66% and 72%, respectively. With natural attenuation, there was a limited removal efficiency, in the order of 2%. Even if the electromagnetic properties evidenced different kinetics of bioremediation in BS and BS + IN, both were able to successfully degrade similar percentages of the contaminant after 8 months. The long monitoring revealed that a substantial decrease in the electromagnetic properties happened only in the first month after contamination. Additionally, an increasing trend of the permittivity was detected in the following months, before reaching a steady-state condition. This study revealed that biodegradation processes with acceptable overall removal efficiency can be monitored successfully by observing the variations in the electromagnetic properties.

Histopathological responses and recovery in gills and liver of Nile tilapia (Oreochromis niloticus) exposed to diesel oil

Water pollution due to crude oil has become one of the major means of pollution lately. We experimented to study to what extent different concentrations of diesel oil can distress the gills and liver of the affected fish. Two groups of Nile tilapia (Oreochromis niloticus) were exposed to 0.1 ml/l and 0.5 ml/l diesel oil for seven days and then kept in pollutant-free water for 14 days to scrutinize how much they can recover. A control group has also maintained during the experiment. Several histo-pathological abnormalities were observed in gills including deformed pillar system, clubbed tips in the secondary lamellae, hyperplasia of the epithelial cells, aggregation of cells of the primary lamellae, fusion of secondary lamellae, telangiectasia and lamellar aneurysms. Though almost similar level of aberration was observed in the lower and higher treatment group, fish treated with lower concentrations were quick to recover. When it comes to the liver, fish treated with 0.1 ml/l diesel showed mild necrosis, patchy degeneration, hypertrophy nucleus and which eventually recovered after 14 days of the recovery period, whereas fish treated with 0.5 ml/l diesel showed moderate to severe abnormalities in almost all cases and the recovery was less but pattern was observed. The experimental study concluded that the higher the exposure to diesel oil, higher incidences of major health problems are recorded, seriously piercing the healing system of Nile tilapia.

Bioremediation of oily seawater by Bacteria immobilization on a novel carrier material containing nutrients

A novel carrier material was obtained by coating puffed rhubarb rice (PRR) with calcium alginate (CA) membrane. The carrier material was prepared to contain oil-degrading bacterial strains and inorganic nutrients through entrapping them in different locations. This formulation possessed floatability, biodegradability and nutrient slow-release properties. Therefore, it could be applied for oil biodegradation on seawater surfaces. For controlling the release rate of nutrients, the optimal preparation technique was established. The number of viable cells immobilized on the carrier material reached 2 × 109 CFU/g. This formulation could be stored at −20 °C for three months without a significant decrease in the number of viable immobilized cells (4 × 108 CFU/g). Scanning electron microscope (SEM) results showed that the cells were immobilized on the outer CA membrane, and the inorganic nutrients were entrapped in the inner PRR and CA membrane. The immobilized cells were able to remove 86% of the diesel oil at an initial diesel oil concentration of 1% (v/v), an incubation temperature of 37 °C, during three days of incubation. Gas chromatography-mass spectrometry (GC–MS) analysis results showed that most components of diesel oil were degraded by the formulations.

Bioremediation potential of hydrocarbon degrading bacteria: isolation, characterization, and assessment.

Oil contamination is a worldwide concern now. However, oil contaminated environment is enriched with microorganisms that can utilize petroleum oil and use hydrocarbon for their growth, nutrition and metabolic activities. In the present study, bacteria present in the oil contaminated soil were isolated by enrichment culture technique using Minimal Salt (MS) media supplemented with diesel oil and burned engine oil as a sole carbon source. The isolated bacteria were characterized by morphological and biochemical tests and identified by molecular tool through cycle sequencing method. Three isolates were morphologically characterized as gram-negative, cocci shaped and 16S rRNA sequence analysis revealed that the isolates are closely related to Pseudomonas sp., Acinetobacter sp., and Enterobacter sp. respectively. Growth condition was optimized at pH 7.0 and temperature 37 °C. All the isolates were susceptible to several antibiotics and they have no antagonistic effect with soil beneficial bacteria. Three isolates were grown in two different concentrations of diesel oil and burned engine oil (4% v/v and 8%, v/v) respectively. Study revealed that with increasing the concentration of diesel oil in the media the growth rate of all the isolates were decreased. In contrast, the growth rates of all the three isolates were increased, with increasing concentration of burned engine oil. In our study, all the isolates showed their degradation efficacy in 4% v/v diesel oil and in 8% v/v burned engine oil. So, our research clearly shows that the isolates could be potentially used for bioremediation purposes for cleaning up petroleum polluted area.

Integrated use of chemical and geophysical monitoring to study the diesel oil biodegradation in microcosms with different operative conditions

This study aimed to monitor the aerobic bioremediation of diesel oil-contaminated soil by measuring: a) the CO2 production; 2) the fluorescein production; 3) the residual diesel oil concentration. Moreover, the complex dielectric permittivity was monitored through an open-ended coaxial cable. Several microcosms were prepared, changing the water content (u% = 8–15% by weight), the carbon to nitrogen ratio (C/N = 20–450), and the soil amount (200 and 800 g of dry soil). The cumulative CO2 and fluorescein production showed similar trends, but different values since these two parameters reflect different features of the biological process occurring within each microcosm. The diesel oil removal efficiency depended on the microcosm characteristics. After 84 days, in the microcosms with 200 g of dry soil, the highest removal efficiency was achieved with a water content of 8% by weight and C/N = 120, while in the microcosms with 800 g of dry soil the best result was achieved with the water content equal to 12% by weight and C/N = 100. In the tested soil, the bioremediation process is efficient if the water content is in the range 8–12% by weight, and C/N is in the range 100–180; under these operative conditions, the diesel oil removal efficiency was about 65–70% after 84 days. The dielectric permittivity was monitored in microcosms with 200 g of dry soil. The open-ended coaxial cable detected significant variations of both the real and the imaginary component of the dielectric permittivity during the bioremediation process, due to the physical and chemical changes that occurred within the microcosms.

Behaviour and morphology pattern analysis of Indian major carps fingerlings exposed to commercial diesel oil suspension

ABSTRACT Increased demand for commercial petroleum derivatives, including diesel has increased the possibility of numerous spills and leakages into the aquatic environment worldwide that can directly or indirectly pollute waterbody disrupting the health status of fish species and other aquatic organisms. This study was conducted to understand the effects of commercial diesel oil on freshwater species of rui (Labeo rohita), catla (Catla catla), and mrigal (Cirrhinus mrigala) fingerlings. The fingerlings were exposed to four different concentrations (0; 0.25; 0.50 and 0.75 ppm) of diesel oil, each containing three replications for 96 h. After 96 h lethal concentration (LC50) for rui, 0.35 ppm; catla, 0.30 ppm; and mrigal fingerlings 0.3625 ppm, were calculated through probit analysis. Maximum mortality occurred at the highest concentration of diesel oil, and treated fingerlings showed behavioural and external morphologic alterations. Dissolved oxygen decreased with the increasing of oil concentrations, and water quality was poor among all the treatments. This study demonstrated that commercial diesel oil directly affects the survivability, behaviour, and external morphology of rui, catla, and mrigal fingerlings. It is expected that the present results will be beneficial to make awareness of the fretful effects of commercial diesel oil and other oils uses in the environment.

Isolation and characterization of a high-efficiency marine diesel oil-degrading bacterium

In the recent 50 years, marine oil spills had resulted in severe environmental pollution problems worldwide. In this study, 12 petroleum-degrading strains named MJ1 to MJ12, which can use diesel oil as the sole carbon source for growth, were isolated from the seawater in Jiaozhou Bay, China. Strain MJ4 has the highest diesel-degrading rate which is up to 26.54% in 5 days with the diesel oil concentration of 10 g/L. According to the BLAST research, 16SrRNA sequence of MJ4 showed 99% similarity to Bacillus megaterium strain. Single-factor experiments and response surface methodology were carried out to optimize the environmental factors and their reciprocal action for affecting the diesel oil degradation process of Bacillus sp. MJ4. Results of single-factor experiments revealed that the highest degradation rate was obtained with temperature of 28 °C, pH of 8.8, diesel oil concentration of 25 g/L, P/N ratio of 0.56, nitrogen and phosphorus dosage quantity of 0.35 g/L and 0.18 g/L, respectively. A nonlinear regression equation of diesel oil degradation rate and pH, temperature, P/N ratio was obtained. The model predicted the maximum degradation rate of 72.21% with temperature of 28 °C, pH of 8.88, P/N ratio of 0.31, respectively.

Hydrocarbon holding capacity of the coconut endocarp in oily water

En la investigación se evaluó el uso de un material filtrante, a base de endocarpio o cáscara de coco (Cocos nucifera) de forma granular, para el tratamiento de aguas contaminadas con gasoil de petróleo a nivel de laboratorio. Se construyó un sistema de filtros con tubos PVC y se empacaron con el endocarpio luego de ser triturado hasta un diámetro de 2 mm. Se utilizaron cinco cantidades de material filtrante (75, 105, 135, 150 y 165 g) y tres concentraciones de gasoil en agua (5, 10 y 15 %). Las muestras de agua contaminada se dejaron fluir a través de los filtros de forma descendente por acción gravitacional y a cada filtrado se le determinó la cantidad de aceites y grasas (AyG), mediante normas internacionales. Los resultados se analizaron estadísticamente mediante ANOVA factorial y test de mínima diferencia significativa de Fisher. Los análisis estadísticos demostraron que existe influencia significativa de los dos factores (% gasoil y cantidad de material filtrante) sobre la variable respuesta en estudio (AyG) con un nivel de confianza de 95 %. Se demostró que el endocarpio de coco con el tamaño de granos utilizado, es efectivo para la remoción de hidrocarburos en el agua, logrando porcentajes de remoción de 85.10, 84.23 y 82.10 %. Se obtuvo que a mayor cantidad del material filtrante, mayor es el grado de remoción con resultados estadísticamente significativos.