Biodegradation Of Oily Sludge Research Articles

Assessment of oily sludge biodegradation in lab scale composting and slurry bioreactor by bacterial consortium

The present study aimed to investigate biodegradability of oily sludge in lab scale composting and slurry bioreactor using a potential bacterial consortium isolated from petroleum-contaminated sites. The consortium used in the study consisted of bacterial genera, including Enterobacter, Bacillus, Microbacterium, Alcaligenes Pseudomonas, Ochrobactrum, Micrococcus, and Shinella which were obtained after rigorous screening using different hydrocarbons. The meticulously designed lab scale composting experiments were carried out and showed that the combination of 10% oily sludge (A1) exhibited the highest total carbon (TC) removal, which was 40.33% within 90 days. To assess the composting experiments' efficiency, the first (k1) and second (k2) order rate constants were evaluated and was found to be 0.0004–0.0067 per day and second (k2) 0.0000008–0.00005 g/kg. day respectively. To further enhance the biodegradation rate of A1 combination, a slurry bioreactor was used. The maximum total petroleum hydrocarbon (TPH) removals in a slurry bioreactor for cycle-I and –II were 48.8% and 46.5%, respectively, on the 78th and 140th days of the treatment. The results obtained in the study will be a technological platform for the development of slurry phase treatment of petroleum waste in a sustainable and eco-friendly manner.

Identification of hydrocarbon-degrading bacterial consortium isolated from the oil-contaminated muddy soil in Hanoi, Vietnam

Bioremediation is a promising approach for treating oil-contaminated environments. The main objective of this study was to isolate bacteria capable of degrading hydrocarbons for application in oily wastewater treatment from oil-contaminated sites in Hanoi, Vietnam. The bacterial consortium studied was obtained from an oil-contaminated muddy soil sample enriched with crude oil mixed with diesel oil as a carbon source. The reconstituted consortium was able to degrade 93% of the oil content after 7 days of testing. A total of five pure bacterial strains were isolated on TSA agar from the complex microbial communities and were selected as potential candidates for oily sludge biodegradation processes. These isolates were identified based on their morphological and biochemical characteristics. By using molecular biology techniques, five hydrocarbons degrading bacteria were investigated and identified as Pseudomonas mendocina strain MD1 (OL687411.1), Pseudomonas hydrolytica strain MD2 (OL771695.1), Brucella intermedia strain MD3 (OL687412.1), Pseudomonas stutzeri strain MD4 (OL687413.1), and Stenotrophomonas nitritireducens strain MD5 (OL687414.1). The morphological and biochemical characterization of these bacteria showed that five of them were Gram-negative, rod-shaped, catalase positive, the ideal pH was neutral, and the optimum growth temperature was 30ºC in a culture medium with a salinity of 0.5%. These strains are capable of producing extracellular enzymes, such as lipase, amylase, cellulase, and protease.

Slurry phase biodegradation of heavy oily sludge and evidence of asphaltene biotransformation

Oily sludge management is a global environmental concern due to its hazardous nature. Oily sludge obtained from a refinery in India had 19–21% oil content. The oil was highly enriched in the asphaltene fraction. Slurry phase biodegradation of this oily sludge in presence of a 3-membered bacterial consortium was optimized in presence of Triton X-100 to increase the bioavailability of hydrocarbons. Triton X-100 at 4 times the critical micelle concentration (CMC) showed the highest degradation where oil removal of 53.1% was achieved from a 10% sludge slurry over 90 days. GCxGC analysis of n-alkanes present in the oily sludge after the biodegradation study showed an increase in the lower n-alkanes, i.e., dodecane and tridecane over the first 30 days, whereas the higher n-alkanes were removed to a much higher extent. Heptadecane showed the maximum extent of degradation with 94.9% removal in 90 days and an initial degradation rate of 0.079 day−1. The, maximum rate of degradation was observed for pentacosane (0.083 day−1) with 93.7% removal in 90 days. The increase in the lower n-alkanes may be attributed to biotic transformation of the asphaltene fraction which was also confirmed through FTIR and pyrolysis GCxGC analysis. Biodegradation was found to cause changes in the pyrolysis product of asphaltenes where four and three-ring pyrolysis products decreased while the one and two-ring pyrolysis products increased. In presence of the consortium asphaltene removal over 90 days was 12% whereas only 0.4% removal was obtained in the abiotic controls.

Biotreatment of oily sludge by a bacterial consortium: Effect of bioprocess conditions on biodegradation efficiency and bacterial community structure.

We studied the biodegradation of oily sludge generated by a petroleum plant in Bahrain by a bacterial consortium (termed as AK6) under different bioprocess conditions. Biodegradation of petroleum hydrocarbons in oily sludge (C11-C29) increased from 24% after two days to 99% after 9 days of incubation in cultures containing 5% (w/v) of oily sludge at 40°C. When the nitrogen source was excluded from the batch cultures, hydrocarbon biodegradation dropped to 45% within 7 days. The hydrocarbon biodegradation decreased also by increasing the salinity to 3% and the temperature above 40°C. AK6 tolerated up to 50% (w/v) oily sludge and degraded 60% of the dichloromethane-extractable oil fraction. Illumina-MiSeq analyses revealed that the AK6 consortium was mainly composed of Gammaproteobacteria (ca. 98% of total sequences), with most sequences belonging to Klebsiella (77.6% of total sequences), Enterobacter (16.7%) and Salmonella (5%). Prominent shifts in the bacterial composition of the consortium were observed when the temperature and initial sludge concentration increased, and the nitrogen source was excluded, favoring sequences belonging to Pseudomonas and Stenotrophomonas. The AK6 consortium is endowed with a strong oily sludge tolerance and biodegradation capability under different bioprocess conditions, where Pseudomonas spp. appear to be crucial for hydrocarbon biodegradation.

Biotreatment of oil sludge containing hydrocarbons by Proteus mirabilis SB

The release of petroleum hydrocarbons in the form of oil sludge poses a serious threat to people and the environment. At present, biodegradation of oily sludge is regarded as one of the most promising harmless treatment technologies, where the screening of high efficient degrading strains is the key to its implementation. In the present study, a strain Proteus mirabilis SB was isolated from oil sludge of Jingbian Oil Field. The strain grew and reproduced rapidly with petroleum hydrocarbon as the sole carbon source in the optimal growth temperature range of 30–35 °C, and salinity less than 6%. Its effective emulsification function was attributed to the production of biosurfactants, mainly rhamnolipids, through metabolism. Analysized by gas chromatography (GC) and four-fraction the degradation efficiency of total petroleum hydrocarbon (TPH) reached 70.5% within 2 weeks in the liquid culture medium, while the degradation efficiencies of saturated hydrocarbons, aromatics, resins and asphaltenes were 90.8%, 69.2%, 16.3% and 31.5%, respectively. For degrading petroleum hydrocarbons in oil sludge within a quasi-solid culture system under standard atmospheric conditions, a total degradation efficiency of 76.9% over 60 days was obtained, while 90.8% of saturated hydrocarbons and 69.2% of aromatics were degraded. Overall, the strain was capable of degrading petroleum hydrocarbons in both crude oil and oil sludge with high efficiencies This development demonstrated strong potential of Proteus mirabilis SB for oil sludge treatment and in situ bioremediation of crude oil contaminated soil/land.

Oilfield waste treatment using novel hydrocarbon utilizing bacterial consortium — A microcosm approach

Oily sludge is a hazardous waste generated through petroleum producing and processing industrial units. Due to its harmful environmental impacts, it needs to be treated in sustainable manner. The present study aimed to evaluate influence of bioaugmentation on oily sludge biodegradation efficiency of a novel hydrocarbon utilizing bacterial consortium (HUBC) using microcosms. Three approaches (bioaugmentation, natural attenuation and abiotic factors) were used for microcosm studies. Bioaugmentation treatment showed best results for oily sludge degradation than natural attenuation and abiotic factors, resulting 82.13 ± 1.21% oily sludge degradation in 56 days. In bioaugmented microcosm on 56th day 0.30 ± 0.07 × 108 CFU/g hydrocarbon utilizing bacteria were noted. Results showed that HUBC could be used to remediate soil polluted with oily sludge. This study imparts a notable approach for farming application(s).

Experiments and Modeling for Investigation of Oily Sludge Biodegradation in a Wastewater Pond Environment

Historic operating and abandoned refineries frequently contain ponds or lagoons that contain oily sludge from historic wastewater treatment processes and separator sludge disposal activities that occurred prior to the implementation of regulations forbidding such disposal. These oily sludge-containing wastewater ponds represent a long-term liability at older operating refineries or abandoned refinery sites. Dewatering and solidification/stabilization are the most common technologies used to treat these sludges; however, these approaches are labor, equipment, and material-intensive. For sites where the time required to complete treatment is not a high priority, biodegradation treatment may be effective for final site remedy. The objective of this study was to investigate potential improvements in oily material biodegradation using dispersants and petroleum-degrading microbial consortia, along with the modeling of this system. The oil dispersed with mixing or remaining in the bulk aqueous phase with biodegradation was measured using methods from a dispersant effectiveness test. The experimental results indicated that mixing at levels of 200 rpm or higher resulted in positive effects on both the extent of hydrocarbon dispersion (80 to 90% of oil dispersed) and the biodegradation of the oil phase (50 to nearly 100% degraded), while the modeling results, taken along with the experimental results, indicated smaller dispersed phase droplet sizes and promoted more efficient biodegradation.

Kinetic study of oily sludge biodegradation under shaking condition

In this research, the biodegrade ability of oily sludge was investigated. Two bacterial strains isolated from the oil storage tank were identified as Aneurinibacillus migulanus and Bacillus toyonensis and submitted in the gene bank database National Center for Biotechnology Information (NCBI). Three bacterial treatments consisting of identified isolates with the initial concentration of 2 g/L of the sludge were used to find the best treatment in the utilisation of the oily sludge under a shaking condition. The results of the oily sludge biodegradation with initial concentrations of 20, 50, and 100 g/L during 150 days showed 72.4, 53, and 43.9% hydrocarbon utilisation, respectively. The results of GC chromatograph showed that all hydrocarbon fractions were utilised in nearly the same range. Additionally, kinetic studies revealed that Contois model can accurately predict the oily sludge biodegradation. Monte Carlo method was used to fit the kinetic parameters of the model to experimental data.

A Study on Combination of a Chemical and Biological Method for Oily Sludge Biodegradation

Oily sludge is a waste product of petroleum industries or oil refineries and poses hazardous effect on the environment if released untreated. Treating and disposing such waste product is of major concern and created much difficulties. The several mechanical, chemical and biological ways of treating the wastes are incineration, stabilization/ solidification, oxidation and bio-degradation (bioremediation), etc. These methods have their own advantages and disadvantages. This review is based on co-treatment of the oily-sludge using a chemical method(oxidation) and a biological method(bioremediation). These two methods when combined, considerably increases the percentage of degradation of the oily sludge and decreases the time taken for bioremediation.

Kinetic study of oily sludge biodegradation under shaking condition

Kinetic study of oily sludge biodegradation under shaking condition

Oily sludge biodegradation using a new two-phase composting method: Kinetics studies and effect of aeration rate and mode

Abstract In this research, the impact of active and passive aeration on the performance of a new two-phase composting process for biodegradation of storage tank oily sludge (STOS) was evaluated. The hyphenated method consisted of primary-stage composting (PSC) including three windrow piles and secondary-stage composting (SSC) including four in-vessel bioreactors. Various turning and aeration rates were tested in the PSC and SSC for 12 and 6 weeks, respectively. Results showed that the removal percentages of total petroleum hydrocarbons (TPH) in the PSC and SSC were in the range of 72.13–89.42 and 68.36–81.63%, respectively. An overall TPH removal of 90.07–94.23% reached through the two-stage system was higher than those of both the PSC and SSC alone. The turning and aeration rate of every 5 days and 1 l min−1 kg−1 were, respectively, determined as optimal values. TPH was degradation fitted to the first-order kinetics based on the rate constants and half-lives of 0.114–0.183 d−1 and 3.79–6.08 days for the PSC, and 0.191-0.296 d−1 and 2.34–3.63 days for the SSC, respectively. The bacteria of Staphylococcus sp., Pseudomonas sp., Proteus sp., and Bacillus sp. were isolated from the process. This study verified the effectiveness of the two-phase composting system in STOS bioremediation.

Lysinibacillus sphaericus proved to have potential for the remediation of petroleum hydrocarbons

ABSTRACTIn this study, the ability of Lysinibacillus sphaericus to degrade aromatic hydrocarbons as well as complex hydrocarbon mixtures, such as diesel oil and oily sludge, was evaluated. L. sphaericus was able to grow when toluene, naphthalene, or phenanthrene were used as a sole carbon source in minimal salt medium. Removal efficiencies of up to 95% were found for C10-C28 hydrocarbons in the biodegradation assays of diesel oil. The biodegradation of oily sludge was evaluated in landfarming-like experiments in the open air and in completely covered containers in the field. After 50 days of treatment, the removal efficiency of total petroleum hydrocarbons in open-air and closed assays was of 84.1% and 60.1%, respectively. Furthermore, L. sphaericus was able to degrade volatile hydrocarbons (benzene, toluene, ethylbenzene, and phenol) in the headspace of closed containers, preventing the emission of these compounds to the atmosphere. L. sphaericus was herein proposed as a promising candidate to be used in bioremediation strategies of petroleum hydrocarbons.

Rhizodegradation of Hydrocarbon from Oily Sludge

Rhizoremediation involves the use of plant growth promoting rhizobacteria (PGPR) to remove organic pollutants from terrestrial environment. The main objective of this study was to evaluate the efficiency of rhizoremediation through inoculation of hydrocarbon degrading bacterial strains with and without nutrients in the rhizosphere sporadically become contaminated with oily sludge. Bacterial strains viz. Bacillus cereus (Acc KF859972), Bacillus altitudinis (Acc KF859970), comamonas (Acc KF859971) and Stenotrophomonas maltophilia (Acc KF859973) were isolated from various oily waste pits of oil fields. Autoclaved soil was treated with oily sludge at 7:3 ratio and Alfalfa plant was inoculated with individual plant growth promoting rhizobacteria (PGPR) with and without diammonium phosphate and ammonium nitrate. The different saturates and total hydrocarbon was extracted by Soxhelt extraction and was analyzed by GC-FID at 0, 5 and 10 d of incubation. The inoculation 30% sludge with B. altitudinis accelerated the rate of degradation of n-alkanes and some methyl branched than un-inoculated soils. Oily sludge inoculated with B. altitudinis indicated that more than 80% of hydrocarbons were degraded at day 5 of incubation. No further degradation was observed till the end of the incubation period. B. altitudinis is capable of degrading straight chain hydrocarbons rapidly than any other strains. Alfalfa is a N-symbiotic plant and increased nutrient content under the rhizosphere promote degradation of n-alkanes. All other bacterial strains also showed significant interaction with alfalfa for the biodegradation of oily sludge but the rate of degradation remained slow than with B. altitudinis. Inoculation with B. altitudinis accelerated the rehabilitation process and within 5 days the rehabilitation occurs.

BIOREMEDIATION OF CONTAMINATED SOIL BY SLUDGE OIL USING THE BIOPILES AMELIORATED

The bioremediation of contaminated soil by sludge oil from petroleum refinery using amended biopiles through bio-stimulation and/or bio-augmentation was objective of this work. Four biopiles were constructed as follows: B1. control; B2. Bio-supplemented with oil-sludge-degrading bacteria and fungus; B3. Bio-supplemented and bio-stimulated with nutrients (N and P); B4. Bio-supplemented and bio-stimulated with nutrients and rice husk. The study lasted 50 weeks and three different biodegradation stages were found during this period: an initial stage in which the reduction of oil and grease was greatest (up to 10 weeks); a stage with low biodegradation rates of the residue (10-30 weeks), and a late stage (30-50 weeks) in which it was observed an increase of the oily sludge biodegradation after the biopiles were covered with black plastic in thirtieth week. This procedure increased the internal temperature of biopiles and showed the importance of this parameter in the biodegradation process. The bio-stimulation using rice husk improved soil aeration and allowed the development of microorganisms added and increased their metabolic activities; consequently, the oil and grease removal was greater (79.1%). The bacteria and fungus added in biopiles B2 and B3 did not survive, so it is necessary to produce inoculum more competitive and adapted. The biopiles system proved to be a viable technology for the bioremediation of soil polluted by oily sludge from petroleum refinery and the bio-stimulation by addition of materials such as rice husk increases its efficiency.

Application of the biosurfactants produced by Bacillus spp. (SH 20 and SH 26) and Pseudomonas aeruginosa SH 29 isolated from the rhizosphere soil of an Egyptian salt marsh plant for the cleaning of oil - contaminataed vessels and enhancing the biodegradation of oily sludge

During the screening for biosurfactant-producing bacteria isolated from the rhizosphere soil of an Egyptian salt marsh plant, three bacterial strains (Bacillus spp. SH 20 and SH 26, and Pseudomonas aeruginosa SH 29) were most active strains. Biosurfactants produced by the three bacterial strains were stable at wide range of pH (1 to 14), wide range of temperature (0 to 121°C) and salinity (5 to 15% NaCl). The two Bacillus species were able to produce high E24 values for petroleum oil (75 to 84.4%), while P. aeruginosa was able to produce E24 value of 62%. Accordingly, the sterilized broth culture (supernatants) containing the biosurfactants produced by the two Bacillus spp. were used for enhancing the bioremediation of oily sludge-contaminated soil. On the other hand, the sterilized supernatant of P. aeruginosa was applied for cleaning oil-contaminated vessels. The results show that addition of the supernatant of Bacillus sp. SH 26 stimulated the biodegradation of the oily sludge (34.0% w/w); this is in contrast to biodegradation of 28.0 and 22.2% of the oil in presence of uninoculated medium and the supernatant of Bacillus sp. SH 20. When the contaminated soil was treated with the mixture of the two supernatants of the two Bacillus spp., no biodegradation of the oil above 26.3% was observed. This may indicate inhibitory effect on some of the oil degraders present in this system, due to the presence of the biosurfactant produced by Bacillus sp. SH 20. When the phytogenic biosurfactant was applied as a comparison, it was of interest to find that this biosurfactant was able to degrade 53.8% of the oil, and this represent excellent candidate for enhancing bioremediation of oil contaminated sites. This was followed by the microbial biosurfactant (34%) produced by Bacillus sp. SH 26. The results of cleaning oil-contaminated vessels by applying the supernatant of P. aeruginosa SH 29 show that after 15 min of the addition of the supernatant, the oil was recovered from the bottom and walls of the vessels and floated on the supernatant as a distinct phase. This indicates that the sterilized supernatant of P. aeruginosa SH 29 can be used directly for cleaning oil storage tanks and other vessels used for transportation and storage of crude petroleum oil. Key words: Biosurfactants, Pseudomonas aeruginosa, Bacillus sp., bioremediation, cleaning oil-contaminated vessels

Effect of sulphur species on the hydrocarbon biodegradation of oil sludge generated by a gas processing facility

Oily sludge from gas processing facilities contains components that are major environmental pollutants. Biodegradation is an alternative treatment, but can be affected by other components of the sludge, such as sulphur compounds, so it is important to evaluate the effect of these on oil biodegradation in order to prevent negative impacts. This work studied the transformation of sulphur compounds in oily sludge biodegradation systems at the microcosm level. The predominant sulphur compounds in the original sludge were elemental sulphur and pyrite (9,776 and 28,705.4 mg kg−1, respectively). In the biodegradability assays, hydrocarbon concentrations decreased from 312,705.6 to 186, 760.3 mg kg−1 after 15 days of treatment. After this time, hydrocarbon degrading activity stopped, corresponding with a decrease in hydrocarbon degrading bacteria. These changes were related to a reduction in pH that inhibits biodegradation. During the assay, sulphur compounds were gradually oxidized and transformed. The concentration of sulphate increased from 5,096 to 64,868.3 mg kg−1 after 30 days in the assay, although controls were unchanged. Therefore, it is important to determine changes to the main compounds of the waste in order to assess their impact.

Biodegradation of Total Petroleum Hydrocarbons from Oily Sludge

ABSTRACT The present study concerns the biotreatment of oily sludge of petroleum refineries. Experiments were performed to assess the degradation potential of the microbial species present in the oily sludge through augmentation, and using the augmented microbial inoculums to treat oily sludge in a slurry form containing mineral medium and water. The optimum pH of the slurry was found to be 8 for the biodegradation of oily sludge. The effect of oily sludge concentration, stirring rate, and treatment time on degradation of total petroleum hydrocarbons (TPH) was studied. It was found that the degradation process consists of two consecutive stages and that each stage follows a first-order kinetics. The first stage lasted 4 days followed by a second stage up to 7 days. The faster first stage had a rate constant of 0.1 day−1, whereas the slower second stage had a rate constant of 0.056 day−1. The kinetics was found to be time-dependent. The study showed that the mineral medium provided essential nutrients to the microbial species and that the degradation efficiency of the whole microbial species present in the oily sludge was quite high (∼90%).

Enhanced remediation of an oily sludge with saline water

This study investigates the potentials of saline (that is, brackish) water to enhance the remediation of an oily sludge, which was part of the waste stream from the improvement project of the Tank Farm at the Bonny Island in the Niger Delta region of Nigeria. Twice weekly, five separate laboratory-scale reactors (labeled A, B, C, D and O), each containing 2.0 × 10-2 m3 of the diluted sludge samples, received 170 g of liquid 20:10:10-NPK-fertilizer (corresponding to an application rate of approximately 4.3 kg-N-m-3, 2.1 kg-P-m-3 and 2.1 kg-K-m-3 of diluted sludge). On a weekly basis, control reactors A and B received 5.0 × 10-4 and 1.5 × 10-3 m3 of fresh water respectively while ‘treatment’ reactors C and D received 5.0 × 10-4 and 1.5 × 10-3 m3 of saline water (containing 4.54 g/L of NaCl) respectively. Reactor O, which served as a counterfactual, was only rain-fed. Equal oxygen exposure levels, through regularly scheduled tilling, was maintained in all five reactors. After 12 weeks of treatment (that is, from May to August, 2007), sludge physicochemical characteristics showed distinct variations. The saline water treated-reactor D, had a 7-fold increment in bacterial population while the fresh water treated-reactor B, had an approximately 3-fold increment in bacterial population. The drop in the hydrocarbon content of the saline water-treated reactors ranged from 41.7 to 55.9% whereas in the fresh water-treated reactors, the hydrocarbon losses ranged from 17.3 to 25.0%. These results showed the possibility of enhanced biodegradation of oily sludge by hydrocarbon utilizing bacteria (Bacillus subtilis) at salinity (NaCl concentration) of 4.54 g/L. Key words: Bioremediation, biostimulation, oily sludge, saline water, Bacillus subtilis.

Evaluation of the use of vinasse as a biostimulation agent for the biodegradation of oily sludge in soil

This work aimed to study the effect of vinasse on the biodegradation in soil of oily sludge from the Replan-Petrobras oil refinery. The Bartha respirometric method was used to verify the efficiency of the treatments with soil, oily sludge (7 and 14% m/m) and soil moisture adjustment with or without vinasse (0.11 mL/g dry soil) for 121 days. Although an increase in the soil microbial population was obtained with the vinasse, it demonstrated not to be adequate to enhance the biodegradation efficiency of the oily sludge in soil, since there was no difference between the CO2 produced from treatments with or without vinasse after the complete consumption of the vinasse. Thus, the use of vinasse as an amendment to biodegradation processes showed not to be efficient under the studied conditions.

Efficiency of refinery sludge biodegradation using municipal wastewater and activated sludge and effect of hydrocarbon concentration on culturable bacteria community

The efficiency of activated sludge as inoculum and municipal wastewater as diluent for the biodegradation of refinery sludge was investigated. At a laboratory scale, biodegradation experiments carried out in an aerobic batch reactor showed that toxic oily sludge was biodegradable after dilution. Compared with freshwater, the use of municipal wastewater for dilution clearly enhanced the biodegradation of this toxic pollutant. Using municipal wastewater, experiments showed that, starting from an initial total hydrocarbon concentration (THC) of 750 mg L−1, we could reach a final THC of 5 mg L−1 and a COD removal of 97% in only 19 days. In addition, we found that bacterial dominance was affected by hydrocarbon load. An absolute dominance of Gram-positive strains with high hydrocarbon load (7500 mg L−1) was found. However, with a hydrocarbon load of 750 mg L−1, some Gram-negative strains were also active. This bacterial dominance also changed in the course of treatment. We conclude that municipal wastewater and activated sludge, less often used nowadays in oily sludge biodegradation processes, contained bacterial strains that are efficient and able to work in a community. Municipal wastewater is also strongly recommended as a diluent as it offers an effective low-cost solution.