Biodegradation of petroleum industry oily-sludge using Jordanian oil refinery contaminated soil

The main objective of this study was to evaluate the effect of oily sludge concentration on its biodegradability in soil. Oily sludge was collected and applied to microcosms at full-, half-, or quarter-strength concentrations equivalent to 44.2, 22.2, and 11.1 g kg^?1 soil, respectively, of total petroleum hydrocarbons (TPH) contained in oily sludge. The biodegradability of oily sludge was evaluated by measuring CO₂ evolution and by measuring removal of TPH as well as its main composing fractions; namely; alkanes, aromatics, NSO-compounds, and asphaltenes. The collected soil contained 3.63 × 10⁶ cfu g^?1 soil of hydrocarbon-degrading bacteria, which is satisfactory to drive successful biodegradation of hydrocarbons in soil. These numbers increased significantly with oily sludge addition at a rate proportional to the added TPH reaching 3.35 × 10⁷ cfu g^?1 soil in the half-strength treatment. TPH mineralization rate followed the same pattern. However, TPH-mineralization efficiency was the greatest in quarter-strength treatment at 18.3%. TPH-removal efficiency was also highest in quarter-strength treatment at 30.9%. Nutrients addition caused mineralization inhibition. Since nutrients were added as a ratio of the added carbon, inhibition was the greatest with the highest TPH treatment. While alkanes were degraded, aromatics and asphaltenes were not, and NSO-compounds were enriched. Although SDS was completely biodegradable in soil, its addition promoted mineralization and removal of TPH from soil.     

Optimization of field scale biopiles for bioremediation of petroleum hydrocarbon contaminated soil at low temperature conditions by response surface methodology (RSM)

Ex-Situ Bioremediation has been increasingly viewed as an appropriate remediation technology for hydrocarbon contaminated soils under cold climates conditions in countries like Canada. A response surface methodology (RSM) based on a factorial design was performed to investigate and optimize the effects of the microbial consortia application rate and amount of mature compost amendment on the TPH removal (964 μg g⁻¹ initial concentration). 18 field-scale biopiles (16 m³ each) were constructed, maintained and subjected to different microbial consortium and mature compost application rates under cold climate conditions over a period of 94 days. TPHs removal rates in the range of 74–82% was observed in the treatments setups where mature compost and microbial consortia were used simultaneously, compared to an average 48% of TPHs removal in control setup.The interaction between these two factors were studied and modelled using a statistical regression model, which showed that the microbial consortia application rate, the mature compost amendment and their interactions had a significant effect on TPHs degradation with a coefficient of determination (R²) of 0.88. Furthermore, using a numerical optimization approach, the optimum rates predicted via RSM were estimated at 4.1 ml m⁻³ and 7% for microbial consortia and compost application rates to obtain a maximum TPH removal of 90.7%.     

Microcosm assays and Taguchi experimental design for treatment of oil sludge containing high concentration of hydrocarbons

Microcosm assays and Taguchi experimental design was used to assess the biodegradation of an oil sludge produced by a gas processing unit. The study showed that the biodegradation of the sludge sample is feasible despite the high level of pollutants and complexity involved in the sludge. The physicochemical and microbiological characterization of the sludge revealed a high concentration of hydrocarbons (334,766 ± 7001 mg kg⁻¹ dry matter, d.m.) containing a variety of compounds between 6 and 73 carbon atoms in their structure, whereas the concentration of Fe was 60,000 mg kg⁻¹ d.m. and 26,800 mg kg⁻¹ d.m. of sulfide. A Taguchi L₉ experimental design comprising 4 variables and 3 levels moisture, nitrogen source, surfactant concentration and oxidant agent was performed, proving that moisture and nitrogen source are the major variables that affect CO₂ production and total petroleum hydrocarbons (TPH) degradation. The best experimental treatment yielded a TPH removal of 56,092 mg kg⁻¹ d.m. The treatment was carried out under the following conditions: 70% moisture, no oxidant agent, 0.5% of surfactant and NH₄Cl as nitrogen source.     

Biotreatment of phenol-contaminated wastewater in a spiral packed-bed bioreactor

A spiral packed-bed bioreactor inoculated with microorganisms obtained from activated sludge was used to conduct a feasibility study for phenol removal. The reactor was operated continuously at various phenol loadings ranging from 53 to 201.4 g m⁻³ h⁻¹, and at different hydraulic retention times (HRT) in the range of 20–180 min to estimate the performance of the device. The results indicated that phenol removal efficiency ranging from 82.9 to 100% can be reached when the reactor is operated at an HRT of 1 h and a phenol loading of less than 111.9 g m⁻³ h⁻¹. At an influent phenol concentration of 201.4 g m⁻³, the removal efficiency increased from 18.6 to 76.9% with an increase in the HRT (20–120 min). For treatment of phenol in the reactor, the maximum biodegradation rate (V _m) was 1.82 mg l⁻¹ min⁻¹; the half-saturation constant (K _s), 34.95 mg l⁻¹.     

Statistical analysis and optimization of nitrogen,phosphorus, and inoculum concentrations for the biodegradation of petroleum hydrocarbons by response surface methodology

In order to optimize and evaluate the influence of nitrogen, phosphorus, and inoculum concentrations on the biodegradation of hydrocarbon contaminated effluents, experiments based on central composite design (CCD) method were carried out for 3 days, employing C1 mixed culture and intermittent aeration. The independent variables were nitrogen concentration (X ₁), phosphorus concentration (X ₂), and inoculum concentration (X ₃) and the removal of total petroleum hydrocarbons (TPH) was the dependent variable. The optimized nutrients ratio (C:N:P = 100:20:2.7) and inoculum concentration (1.32 g/l) provided TPH removal of 71.8% after processing for three days. Analysis using gas chromatography identified five hydrocarbons classes: paraffins, isoparaffins, olefins, naphthenics, and aromatics. The naphthenic compounds did not degrade as readily as the other hydrocarbons that were identified. The following degradation percentages were obtained: 87.1% for the paraffins, 77.7% for the isoparaffins, 78.6% for the olefins, 38.4% for the naphthenics, and 71.7% for the aromatics.     

Biodegradation of methyl parathion in the presence of goethite: The effect of Pseudomonas sp. Z1 adhesion

In this research, the influence of goethite on biodegradation kinetic of methyl parathion was investigated in the presence of Pseudomonas sp. Z1. Semipermeable membrane experiments were performed to demonstrate the role of adhesion of degrading bacteria to surface of goethite in biodegradation of methyl parathion. Sorption of methyl parathion and bacteria onto goethite particles were also measured to assess the distribution of methyl parathion and bacteria between water and goethite surface. The first-order degradation rate constant of methyl parathion in different concentrations of goethite was in the order of 0.1 g L⁻¹ > 0.01 g L⁻¹ > 0 g L⁻¹ > 1 g L⁻¹ > 20 g L⁻¹, suggesting the presence of low concentrations of goethite accelerated the biodegradation of methyl parathion and high concentrations of goethite inhibited this biodegradation process. According to the result of semipermeable membrane experiment, when no bacterial attachment occurred in the system, the promotive effect of 0.1 g L⁻¹ goethite for microbial degradation was disappeared and the inhibition effect of 20 g L⁻¹ goethite increased. The results clearly demonstrated that the adhesion of bacteria to goethite was beneficial to the biodegradation of methyl parathion. The information obtained is of fundamental significance for the understanding of microbial degradation of organic pollution in soil.     

Biodegradation of petroleum hydrocarbons by filamentous fungi (Aspergillus ustus and Purpureocillium lilacinum) isolated from used engine oil contaminated soil

The use of microorganisms for remediation and restoration of hydrocarbons contaminated soils is an effective and economic solution. The current study aims to find out efficient telluric filamentous fungi to degrade petroleum hydrocarbons pollutants. Six fungal strains were isolated from used engine (UE) oil contaminated soil. Fungi were screened for their ability to degrade crude oil, diesel and UE oil using 2.6-dichlorophenol indophenol (DCPIP). Two isolates were selected, identified and registered at NCBI as Aspergillus ustus HM3.aaa and Purpureocillium lilacinum HM4.aaa. Fungi were tested for their tolerance to different concentration of petroleum oils using radial growth diameter assay. Hydrocarbons removal percentage was evaluated gravimetrically. The degradation kinetic of crude oil was studied at a time interval of 10 days. A.ustus was the most tolerant fungi to high concentration of petroleum oils in solid medium. Quantitative analysis showed that crude oil was the most degraded oil by both isolate; P. lilacinium and A. ustus removed 44.55% and 30.43% of crude oil, respectively. The two fungi were able to degrade, respectively, 27.66 and 21.27% of diesel and 14.39 and 16.00% of UE oil. As compared to the controls, these fungi accumulated high biomass in liquid medium with all petroleum oils. Likewise, crude oil removal rate constant (K) and half-lives (t_1/2) were 0.02 day⁻¹, 34.66 day and 0.015 day⁻¹, 46.21 day for P. lilacinium and A. ustus, respectively. The selected fungi appear interesting for petroleum oils biodegradation and their application for soil bioremediation require scale-up studies.     

Continuous cultures of <Emphasis Type="Italic">Pseudomonas putida</Emphasis> mt-2 overcome catabolic function loss under real case operating conditions

The long-term performance and stability of Pseudomonas putida mt-2 cultures, a toluene-sensitive strain harboring the genes responsible for toluene biodegradation in the archetypal plasmid pWW0, was investigated in a chemostat bioreactor functioning under real case operating conditions. The process was operated at a dilution rate of 0.1 h⁻¹ under toluene loading rates of 259 ± 23 and 801 ± 78 g m⁻³ h⁻¹ (inlet toluene concentrations of 3.5 and 10.9 g m⁻³, respectively). Despite the deleterious effects of toluene and its degradation intermediates, the phenotype of this sensitive P. putida culture rapidly recovered from a 95% Tol⁻ population at day 4 to approx. 100% Tol⁺ cells from day 13 onward, sustaining elimination capacities of 232 ± 10 g m⁻³ h⁻¹ at 3.5 g Tol m⁻³ and 377 ± 13 g m⁻³ h⁻¹ at 10.9 g Tol m⁻³, which were comparable to those achieved by highly tolerant strains such as P. putida DOT T1E and P. putida F1 under identical experimental conditions. Only one type of Tol⁻ variant, harboring a TOL-like plasmid with a 38.5 kb deletion (containing the upper and meta operons for toluene biodegradation), was identified.     

Enzymatic production of trans-4-hydroxy-l-proline by proline 4-hydroxylase

Trans-4-hydroxy-l -proline (Hyp) is a useful chiral building block for production of many nutritional supplements and pharmaceuticals. However, it is still challenging for industrial production of Hyp due to heavy environmental pollution and low production efficiency. To establish a green and efficient process for Hyp production, the proline 4-hydroxylase (DsP4H) from Dactylosporangium sp. RH1 was overexpressed and functionally characterized in Escherichia coli BL21(DE3). The recombinant DsP4H with l -proline as a substrate exhibited K_m, k_cat and k_cat/K_m values up to 0.80 mM, 0.52 s⁻¹ and 0.65 s⁻¹·mM⁻¹ respectively. Furthermore, DsP4H showed the highest activity at 35°C and pH 6.5 towards l -proline. The highest enzyme activity of 175.6 U mg⁻¹ was achieved by optimizing culture parameters. Under the optimal transformation conditions in a 5-l fermenter, Hyp titre, conversion rate and productivity were up to 99.9 g l⁻¹, 99.9% and 2.77 g l⁻¹ h⁻¹ respectively. This strategy described here provides an efficient method for production of Hyp and thus has a great potential in industrial application.     

Biodegradation of bisphenol A by bacterial consortia

The effect of light on BPA degradation by an adapted bacterial consortium was investigated. BPA was completely degraded up to 50 mg l⁻¹, and the degradation followed first-order reaction kinetics both in the light and in the dark. The degradation half-life of BPA when the consortium was grown in presence of light was 21.9, 17.2, and 12.6 h for concentrations of 10, 20, and 50 mg l⁻¹, respectively; the degradation half-life of BPA in the dark was 13.1, 10.8, and 10.2 h for concentrations of 10, 20, and 50 mg l⁻¹, respectively. Therefore, light inhibited BPA biodegradation. However, under both conditions, BPA was completely depleted. The bacterial consortium effectively utilised BPA as a growth substrate to sustain a cell yield of 0.95 g g⁻¹ and 0.97 g g⁻¹ in the light and dark, respectively. A total of ten and nine biodegradation intermediates were detected in the light and dark, respectively. Three bacterial metabolic pathways and one photodegradation pathway were proposed to explain their occurrence. This study demonstrated that bacterial consortia may assemble a wide range of catabolic pathways to allow for efficient degradation of BPA, converting BPA to principally bacterial biomass and metabolites exhibiting low or no oestrogenic activity.     

Effects of nitrogen source and empty bed residence time on the removal of styrene gaseous emissions by biotrickling filtration

The removal of styrene-polluted air emissions by biotrickling filtration was performed to evaluate the influence of using nitrate and urea as a nitrogen source in the nutrient solution supplied to two bioreactors run in parallel under the same operational conditions for 3 months. The use of urea resulted in less biomass content along the packed bed and better performance of the process, with a maximum elimination capacity (EC) of 57.6 g C m⁻³ h⁻¹ (removal efficiency (RE) of 88.3% and empty bed residence time (EBRT) of 60 s), which was around 54% higher than when using nitrate. EBRTs of 60, 30 and 15 s were evaluated with a urea-based nutrient supply. By decreasing the EBRT from 60 to 30 s the styrene concentration that could be treated with REs above 80% was almost the half, from 1,100 to 600 mg C m⁻³, resulting in ECs of 52.8 g C m⁻³ h⁻¹. Working at 15 s was not possible to obtain REs higher than 40% with a maximum EC of 28.5 g C m⁻³ h⁻¹.     

Effect of shear on morphology,viability and metabolic activity of succinic acid-producing Actinobacillus succinogenes biofilms

Two custom-designed bioreactors were used to evaluate the effect of shear on biofilms of a succinic acid producer, Actinobacillus succinogenes. The first bioreactor allowed for in situ removal of small biofilm samples used for microscopic imaging. The second bioreactor allowed for complete removal of all biofilm and was used to analyse biofilm composition and productivity. The smooth, low porosity biofilms obtained under high shear conditions had an average cell viability of 79% compared to 57% at the lowest shear used. The maximum cell-based succinic acid productivity for high shear biofilm was 2.4 g g⁻¹DCW h⁻¹ compared to the 0.8 g g⁻¹DCW h⁻¹ of the low shear biofilm. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays confirmed higher cell metabolic activities for high shear developed biofilm compared to biofilm developed at low shear conditions. Results clearly indicated that high shear biofilm cultivation has beneficial morphological, viability, and cell-based productivity characteristics.

     

Design of a new rotating drum bioreactor operated at atmospheric pressure on the bioremediation of a polluted soil

This paper reports the effect of the operation and design characteristics of rotating drum bioreactors (RDBs) aerated by natural convection and applied to the treatment of a soil highly polluted with weathered total petroleum hydrocarbons (TPH) (55,000 ± 2,600 mg/kg). The parameters studied were length to diameter ratio (L/D), rotating speed (N) and lifter type. The highest TPH removal (59.6 ± 0.7%) was obtained with the RDB of the lowest L/D ratio (1.5). Removals diminished by 27, 36 and 56%, with a ratio increment of 2.1, 3.1 and 5.1, respectively. Increment of the N, at an optimal value and lifter change from straight to helicoidal showed an improvement on the TPH removal of 20 and 30%, respectively. According to these results, slurry surface renewal through the variation of the N and the change of slurry flow was able to improve TPH removal in RDBs operated by natural convection.     

Performance and macrokinetic analysis of biofiltration of toluene and p-xylene mixtures in a conventional biofilter packed with inert material

Interactions of toluene and p-xylene in air treatment biofilters packed with an inert filter media were studied. The effect of the inlet load of toluene, p-xylene and mixtures of both compounds on the biodegradation rate was analyzed in three lab-scale biofilters. A maximum elimination capacity (EC) of 26.5 and 40.3 g C m⁻³ h⁻¹ for an inlet load (IL) of 65.6 and 57.8 g C m⁻³ h⁻¹ was obtained for p-xylene and toluene biofilters, respectively. Inhibition of p-xylene biodegradation by the presence of toluene took place when the mixture was treated, whereas the presence of p-xylene had an enhancing effect on the toluene removal efficiency. Specific growth rates (μ) from 0.019 to 0.068 h⁻¹ were calculated in the mixed biofilter, where the highest values were similar to mixtures with lower p-xylene levels (IL_p-Xyl 8.84 ± 0.29 g C m⁻³ h⁻¹). Michaelis-Menten and Haldane type models were fitted to experimental EC for p-xylene and toluene biofilters, respectively.     

Acetone biodegradation in a trickle-bed biofilter

Laboratory scale-studies on acetone biodegradation in a trickle-bed biofilter were carried out using using two identically sized columns, one of which was packed with coconut fibre and the other with plexiglass chips. The columns were inoculated with two strains of bacteria: Burkholderia cepacia (syn. Pseudomonas cepacia) and Acinetobacter baumannii. The continuous process of air purification was carried out at incremental acetone concentrations from 0.3 to 2.5 g m⁻³ air and air flow-rates from 0.1 to 0.3 m³ h⁻¹. A maximum acetone elimination capacity of 95.8 g m⁻³ filter bed h⁻¹ was achieved at air flow-rate of 36 m h⁻¹.     

Impact of substrates acclimation strategy on simultaneous biodegradation of hydrogen sulfide and ammonia

Three columns were differentiated with feeding mixture of H₂S and NH₃ (MFC), feeding NH₃ followed by H₂S (NFC), and feeding H₂S followed by NH₃ (SFC). Removal performance, biodegradation capacity and microbial community structures in the three columns were compared. The results show that NFC has a shorter acclimation period for the removal of NH₃ gas and nitrification than MFC. Under the high loading of H₂S and NH₃ at 164 and 82 g m⁻³ h⁻¹, respectively, NFC exhibited high removal efficiency of NH₃ (>95%) while the removal efficiencies were obtained at 63 and 75% in MFC and SFC, respectively. The removal of NH₃ gas in NFC was significantly attributed to nitrification (over 50%), while adsorption and chemical reaction contributed to the removal of NH₃ in MFC and SFC. The different biodegradation capacities of NH₃ could be due to the dissimilarity in the microbial population presented in each column.     

Microbial nitrogen removal of ammonia wastewater in poly (butylenes succinate)-based constructed wetland: effect of dissolved oxygen

Constructed wetland (CW) is popular in wastewater treatment for its prominent advantage of low construction and operation cost. However, the nitrogen removal in conventional CW is usually limited by the low dissolved oxygen (DO) and insufficient electron donor. This paper investigated the nitrogen removal performance and mechanisms in the poly (butylenes succinate)-based CW (PBS-CW) while treating ammonia wastewater under different DO levels. The average DO contents in limited-aeration and full-aeration phases were 1.68 mg L⁻¹ and 5.71 mg L⁻¹, respectively. Results indicated that, with the ammonia nitrogen loading rate of 25 g N m⁻³ day⁻¹, total nitrogen removal ratios in the PBS-CW under the limited-aeration and full-aeration phases were 72% and 99%, respectively. Combined analyses revealed that simultaneous nitrification and denitrification (SND) via nitrite/nitrate were the main microbial nitrogen removal pathways in the aeration phase of the PBS-CW (> 89%). The microbial carrier of biodegradable material was believed to play a significant role in prompting SND performance while dealing with low C/N wastewater. Due to the coexistence of micro-anaerobic zone and carbon supply inside the coated biofilm, the high DO level in the PBS-CW increased the abundance of the nitrifying bacteria (amoA and nxrA), denitrifying bacteria (narG, nirK, nirS, and nosZ), and even anammox bacteria (anammox 16s rRNA). These features are beneficial to many microbial processes which require the simultaneous aerobic, anoxic, and anaerobic environment.

     

Isolation and characterization of Pseudomonas stutzeri QZ1 from an anoxic sulfide-oxidizing bioreactor

Bacterial strain QZ1 was isolated from sludge of anoxic sulfide-oxidizing (ASO) reactor. Based on 16S rDNA sequence analysis and morphological characteristics, the isolate was identified as Pseudomonas stutzeri. The isolate was found to be a facultative chemolithotroph, using sulfide as electron donor and nitrite as electron acceptor. The strain QZ1 produced sulfate as the major product of sulfide oxidation, depending on the initial sulfide and nitrite concentrations. The isolate was capable of growth under strictly autotrophic conditions. The growth and substrate removal of Pseudomonas stutzeri QZ1 were optimal at an initial pH of 7.5–8.0 at 30 °C. The specific growth rate (μ) was found as 0.035 h⁻¹ with a doubling time of 21.5 h. For isolate QZ1, the EC₅₀ values both for sulfide and nitrite were found to be 335.95 mg S L⁻¹ and 512.38 mg N L⁻¹, respectively, showing that the sulfide oxidation into sulfate by Pseudomonas stutzeri QZ1 was badly affected beyond these substrate concentrations.     

Biostimulation and Phytoremediation Treatment Strategies of Gasoline-Nickel Co-Contaminated Soil

This study investigated the potential effect of poultry dung (biostimulation) and stubborn grass (Sporobolus pyramidalis) (phytoremediation) on microbial biodegradation of gasoline and nickel uptake in gasoline-nickel-impacted soil. In addition, the potential stimulatory effects of nickel on hydrocarbon utilization were investigated over a small range of nickel concentrations (2.5–12.5 mg/kg). The results showed that an increase in nickel concentration increased hydrocarbon degraders in soil by a range of 8.4–17.2% and resulted in a relative increase in gasoline biodegradation (57.5–62.4%). Also, under aerobic conditions, total petroleum hydrocarbons’ (TPH) removal was 62.4% in the natural gasoline-nickel microcosm (natural attenuation), and a maximum of 78.5%, 85.7%, and 95.8% TPH removal was obtained in phytoremediation, biostimulation, and a combination of biostimulation- and phytoremediation-treated microcosms, respectively. First-order kinetics described the biodegradation of gasoline and nickel uptake very well. Half-life times obtained were 28.88, 18.24, 14.44, and 8.56 days for gasoline degradation under natural attenuation, phytoremediation, biostimulation, and combined biostimulation and phytoremediation treatment methods, respectively. The results indicate that these remediation methods have promising potential for effective remediation of soils co-contaminated with petroleum hydrocarbons and heavy metals.     

Biodegradation of heavy oily sludge by a two-step inoculation composting process using synergistic effect of indigenous isolated bacteria

The impact of two-step inoculation of indigenous strains and their synergistic effect in the scaling-up of petroleum hydrocarbons biodegradation from a mineral-based medium (MBM) to a two-phase composting process were investigated. After isolating the strains KA3 and KA4 from heavy oily sludge (HOS), their emulsification index (E₂₄), bacterial adhesion to hydrocarbon (BATH), and oil degradation efficiency were evaluated in the MBM. Then, they were inoculated twice into the composting bioreactors lasted for the primary 8 weeks as the first phase (FP) and subsequent 8 weeks as the second phase (SP). The results indicated that the consortium of the two strains degraded 16-61% of crude oil (1-5% concentration) in the MBM. In the composting reactors, removals of 20 g kg⁻¹ initial concentration of total petroleum hydrocarbons (TPH) were found to be 63.95, 61.00, and 89.35% for the strains KA3, KA4, and their consortium, respectively. The computed biodegradation constants indicated the synergistic effect of the two strains and the effectiveness of the second-step inoculation. The study demonstrated the successful scaling-up of HOS biodegradation from MBM to the two-phase composting process through two-step inoculation of the isolated strains.