Petroleum Remediation Research Articles

Dynamic responses in bioaugmentation of petroleum-contaminated soils using thermophilic degrading consortium HT: Hydrocarbons, microbial communities, and functional genes.

Bioaugmentation offers an effective strategy for the bioremediation of petroleum-contaminated soils. However, little is known about petroleum hydrocarbons (PHs) degradation with thermophilic consortium application under high temperature. A microcosm was established to study hydrocarbons degradation, microbial communities and functional genes response using a thermophilic petroleum-degrading consortium HT. The results showed that the consortium HT significantly enhanced PHs degradation, particularly for medium (C16-C21) (87.1 %) and long-chain alkanes (C21-C40) (67.2 %) within 140 days under high temperature. Colonization of HT in the soil exhibited lagged characteristics, with a substantial increase in bacterial genera originated from the HT after 60 days. Additionally, LEfSe analysis indicated that the biomarkers of HT treatment were mainly from the HT consortium. Moreover, functional analysis revealed genes related to n-alkane degradation (AlkB, P450, LadA), alkane utilization regulator (AraC, TetR, GntR), as well as several thermotolerance genes were significantly increased in HT treatment. Additionally, network analysis demonstrated distinct co-occurrence patterns induced by nutrient addition and exogenous consortium, with the latter strengthening interactions and stability of bacterial networks under high temperature. This study represents pioneering investigation into the effects of exogenous thermophilic consortium on petroleum degradation, bacterial communities, functional genes and ecological interactions in application of petroleum remediation under thermophilic conditions.

Scaled-up production and recovery of lipopeptide biosurfactant and its application for washing petroleum-contaminated drill cuttings

A simple and efficient fermentation strategy using chitosan-immobilized Bacillus subtilis GY19 was developed for large-scale lipopeptide production from waste glycerol and palm oil. When a fed-batch fermentation approach was employed, excessive foaming was minimized, while lipopeptide production was greater than that of conventional batch fermentation. When a 700 L stirred tank fermenter with a 400 L working volume was used, a lipopeptide concentration and yield of 7.55 g/L and 0.190 g/g of substrate, respectively, were achieved. The pilot-scale recovery process involved sequential bacterial cell removal via centrifugation, elimination of impurities through acidification of the cell-free broth, and partial purification and concentration of the lipopeptides via ultrafiltration. A 5 kDa stabilized cellulose-based membrane maintained a constant permeate flux and resulted in 67.2 % lipopeptide recovery. The concentrated lipopeptide retentate contained 16.8 g/L lipopeptides and a surface tension of 28.82 mN/m. A biobased washing agent for the treatment of petroleum-contaminated drill cuttings was later formulated with the retentate and various vegetable oil-based surfactants via the simplex−lattice mixture design methodology. The mixture of 1 % retentate and 4 % fatty alcohol ethoxylate 5EO presented the greatest removal efficiency of 83.2 % for drill cuttings containing 15 % (w/w) total petroleum hydrocarbons. The formulation also mobilized petroleum hydrocarbons into a distinct free oil layer, which would be easy to separate and subsequently recycle. These findings demonstrate the scalability of the lipopeptide production and recovery process, while the biobased washing agent offers an environmentally friendly approach for petroleum remediation.

Enhancement of repeated inoculation strategy with a domesticated bacterial consortium on the biodegradation of high-level crude oil in soil

Repeated inoculation of hydrocarbon degrading microbes should be powerful to improve the survival of inoculant, which is vital to achieve efficient remediation of petroleum contaminated soil. This paper aims to study the repeated inoculation (with different inoculum size and time interval) enhanced bioremediation of high-level petroleum contaminated soil with a domesticated bacterial consortium. The copy number of bacterium and alkB gene, soil enzyme activities and microbial community structure during the remediation were systematically analyzed to preliminarily reveal the mechanism of repeated inoculation affecting remediation for the first time. The results revealed that repeated inoculation remarkably improved the total petroleum hydrocarbon (TPH) removal in soil (86.5 % in HC120) compared with a single inoculation (68.9 % in HA120). The TPH removal of repeated inoculation with high inoculum size (HC) on the 60th day was close to that of once inoculation (HA) on the 120th day, suggesting that repeated inoculation led to faster degradation. Interestingly, the effect of inoculation with low dose and more times (LC120, 78.5 %) was equal to that with high dose and less times (HB120, 78.0 %), even much better than that with high dose and once inoculation (HA120). Treatment HC had a significant impact on the soil bacterial diversity and community structure, and the dominant species in the inoculants, such as Stenotrophomonas and Pseudomonas, which was low abundance in the blank group (CK), still maintained high abundance during the remediation process. The soil catalase activities and the number of alkB gene were the highest in HC. Correlation analysis implied that repeated inoculation of hydrocarbon degrading bacteria did improve the survival of inoculant, soil enzyme activities and maintain the number of degrading bacteria, thus promoting the TPH removal. These findings will facilitate the practical application of bioremediation technology to contaminated environment, which has important environmental and economic benefits.

Mechanism of iron-activated ozone/persulfate coupled oxidation for petroleum-contaminated soil

Soil contamination by petroleum remains a critical environmental challenge. Single oxidation methods, while widely employed for remediation, often exhibit limitations in effectively degrading these contaminants. This hinders their broader application and necessitates the investigation of the complementary effects of commonly employed single oxidation method such as ozone (O3) and persulfate (PS) oxidation to explore their potential for enhanced degradation. In this study, the O3/PS coupling oxidation system activated by iron-loaded activated carbon (Fe@AC) was employed for the remediation of petroleum contaminated soil, and to evaluate the removal efficiency and underlying mechanism for petroleum contaminants. The results demonstrated a significant improvement in the apparent reaction rate constant of the O3/PS/Fe@AC system, recorded at 0.1253 h−1. This rate was approximately twice that of the PS/Fe@AC system (0.0572 h−1) and two orders of magnitude greater than the Fe2+/PS system (0.0014 day−1). Under the conditions of 6 % PS dosage, 0.6 % Fe@AC dosage, a soil-to-water ratio of 1:2, an O3 gas flow rate of 2.5 mg/L, and a pH of 5 at room temperature, the O3/PS/Fe@AC system removed 46.8 % of total petroleum hydrocarbon at an initial concentration of 5000–6000 mg/kg within 3 h. The reaction of the O3/PS/Fe@AC system involved multiple radicals, such as sulfate radicals (SO4•-), hydroxyl radicals (•OH), and superoxide radicals (O2•-), with the reactivity of SO4•- enhanced by O3. This study demonstrates an efficient method for remediating petroleum contaminated soil, providing a theoretical and technical foundation for the application of the O3/PS/Fe@AC system.

Resting for viability: Gordonia polyisoprenivorans ZM27, a robust generalist for petroleum bioremediation under hypersaline stress

The intrinsic issue associated with the application of microbes for practical pollution remediation involves maintaining the expected activity of engaged strains or consortiums as effectively as that noted under laboratory conditions. Faced with various stress factors, degraders with dormancy ability are more likely to survive and exhibit degradation activity. In this study, a hydrocarbonoclastic and halotolerant strain, Gordonia polyisoprenivorans ZM27, was isolated via stimulation with resuscitation-promoting factor (Rpf). Long-term exposure to dual stresses of 10% NaCl and starvation induced ZM27 to enter a viable but nonculturable (VBNC)-like state, and ZM27 cells could be resuscitated upon Rpf stimulation. Notable changes in both morphological and physiological characteristics between VBNC-like ZM27 cells and resuscitated cells confirmed the response to Rpf and their robust resistance against harsh environments. Whole-genome sequencing and analysis indicated ZM27 could be a generalist degrader with dormancy ability. Subsequently, VBNC-like ZM27 was applied in a soil microcosm experiment to investigate the practical application potential under harsh conditions. VBNC-like ZM27 combined with Rpf stimulation exhibited the most effective biodegradation performance, and the initial n-hexadecane content (1000 mg kg−1) decreased by 63.29% after 14-day incubation. Based on 16S rRNA amplicon sequencing and analysis, Gordonia exhibited a positive response to Rpf stimulation. The relative abundance of genus Gordonia was negatively correlated with that of Alcanivorax, a genus of obligate hydrocarbon degrader with the greatest abundance during soil incubation. Based on the degradation profile and community analysis, generalist Gordonia may be more efficient in hydrocarbon degradation than specialist Alcanivorax under harsh conditions. The characteristics of ZM27, including its sustainable culturability under long-term stress, response to Rpf and robust performance in soil microcosms, are valuable for the remediation of petroleum pollution under stressful conditions. Our work validated the importance of dormancy and highlighted the underestimated role of low-activity degraders in petroleum remediation.

Water conditions and arbuscular mycorrhizal symbiosis affect the phytoremediation of petroleum-contaminated soil by Phragmites australis

Phytoremediation of petroleum-contaminated soils using the synergistic functions of plants and rhizosphere microorganisms is a promising technology. However, successfully applying this approach presents challenges under certain conditions (submerged environments). This study analyzed the potential role of Phragmites australis in symbiosis with arbuscular mycorrhizal (AM) fungi during petroleum remediation at two water levels. AM inoculation promoted P. australis aboveground growth under non-flooded conditions, whereas flooding significantly increased P. australis biomass. The highest total petroleum hydrocarbon (TPH) degradation efficiency was observed in non-flooded soils, whereas submergence severely inhibited TPHs dissipation. Plants with AM inoculation treatments substantially enhanced the removal of TPHs under flooded conditions. TPH removal was positively correlated with dehydrogenase activity but negatively correlated with easily extracted glomalin-related soil proteins. Moreover, different petroleum-hydrocarbon-decaying candidates contributed to TPH removal in these two cultured soils. These findings provide valuable information for the remediation of future TPH-contaminated soils, especially applied in intermittently submerged environments.

Correction: Recent advancement in enhanced soil flushing for remediation of petroleum hydrocarbon‑contaminated soil: a state‑of‑the‑art review

Correction: Recent advancement in enhanced soil flushing for remediation of petroleum hydrocarbon‑contaminated soil: a state‑of‑the‑art review

Vapor-phase biodegradation and natural attenuation of petroleum VOCs in the unsaturated zone: A microcosm study

Traditional natural attenuation studies focus on aqueous process in the saturated zone while vapor-phase biodegradation and natural attenuation in the unsaturated zone received much less attention. This study used microcosm experiments to explore the vapor-phase biodegradation and natural attenuation of 23 petroleum VOCs in the unsaturated zone including 7 monoaromatic hydrocarbons, 6 n-alkanes, 4 cycloalkanes, 3 alkylcycloalkanes and 3 fuel ethers. We found that monoaromatic hydrocarbon vapors were easily attenuated with significantly high first-order attenuation rates (9.48 d−1-43.20 d−1) in live yellow earth, of which toluene and benzene had the highest rates (43.20 d−1 and 28.32 d−1, respectively). The 13 aliphatic hydrocarbons and 3 fuel ethers all have relatively low attenuation rates (<0.54 d−1) in live soil and negligible biodegradation contribution. We explored the effects of soil types (black soil, yellow earth, lateritic red earth and quartz sand), soil moisture (2, 5, 10, and 17 wt%) contents and temperatures (4, 15, 25, 35 and 45 °C) on the vapor attenuation. Results showed that increasing soil organic matter (SOM) content, silt content, porosity and soil microorganism numbers enhanced contaminant attenuation and remediation efficiency. Increasing moisture content reduced the apparent first-order biodegradation rates of monoaromatic hydrocarbon vapors. The vapor-phase biodegradation had optimal temperature (∼25 °C in yellow earth) and increasing or decreasing temperature slowed down biodegradation rate. Overall, this study enhanced our understanding of vapor-phase biodegradation and natural attenuation of petroleum VOCs in the unsaturated zone, which is critical for the long-term management and remediation of petroleum contaminated site.

Remediation of petroleum contaminated soil by persulfate oxidation coupled with microbial degradation

This study was conducted on soil polluted with high concentrations of crude oil (12,835 ± 572.76 mg/kg) with different dosages of persulfate (PS) coupled with hydrocarbon-degrading mixed bacteria (including Enterobacteriaceae, Stenotrophomonas, Pseudomonas, Acinetobacter, and Achromobacter) obtained from long-term oil-contaminated soil. The interaction among total petroleum hydrocarbons (TPH), soil parameters, and microbial communities during a 187-d combined remediation process was evaluated. The result showed that the TPH removal of 1% PS oxidation combined with bioremediation was 80.05%; this was 4.88% and 20.94% higher than that of bioremediation and 1% PS oxidation combined with natural attenuation. This is a result of 1%PS stimulated enzyme secretion and dissolved organic carbon content, especially fulvic acid, improving TPH mobility and bioavailability in soil. Furthermore, introducing mixed bacteria after oxidation further increased enzyme activities and TPH-degrading ability, thus promoting carbon substrate conversion and biodegradation rate. Conversely, the excessive oxidation of 3% and 5% PS had a negative impact on the soil environment and microbial diversity resulting in lower TPH degradation (36%-57%). High-throughput sequencing revealed that the abundance and diversity of soil bacteria decreased in all remediation groups compared to those in the pristine soil. Redundancy analysis showed that the main factors affecting 1% PS oxidation combined with bioremediation during subsequent microbial remediation were pH, cation exchange capacity, and lipase activity, which may indirectly influence TPH biodegradation by increasing the abundance of genus Immundisolibacteraceae, Comamonadaceae, and Acinetobacter. This study provides data on in situ chemical oxidation integrated with the bioremediation of petroleum hydrocarbon-contaminated soils.

Review of the application of surfactants in microemulsion systems for remediation of petroleum contaminated soil and sediments.

Microemulsions are important for soil and sediment remediation technology. The characteristics of the surfactants that make up these microemulsions include low sorption into soil or sediments, low surface and interfacial tension, the ability to penetrate tiny pores, and good solubilization of contaminants. This review revealed that microemulsions formulated with nonionic and anionic surfactants have higher recovery efficiencies for hydrophobic contaminants than cationic ones, as evidenced by the surveyed studies reporting effective remediation of soils and sediments using on microemulsions. These microemulsified systems have been found to remove petroleum and its derivatives from soil or sediments at percentages ranging from 40 to 100%. As such, this review can aid with the choice of surfactants used in microemulsions for remediation, such as those with plant-based components, which are promising solutions for the remediation of contaminated soils due to their contaminant extraction efficiency and biodegradability.

Spatial distribution, composition, and source analysis of petroleum pollutants in soil from the Changqing Oilfield, Northwest China

Petroleum contamination surrounding oilfields has attracted more concerns. However, the levels, distribution and source of petroleum of Changqing Oilfield soil still remain lots of knowns, which is important for local environmental protection. Given soil contamination issues in Changqiong Oilfield were investigated. The maximum concentrations of total petroleum hydrocarbons (TPHs), N-alkanes (TNAs) and polycyclic aromatic hydrocarbons (PAHs) were determined to be 1960.29, 96.13 and 0.82 mg/kg, respectively. TPHs were higher in the north than the south of the study area. TPHs decreased in the horizontal and vertical distribution as soil depth and distance from oil wells increased. Source analysis showed that TNAs mainly originated from petroleum, PAHs were controlled by petroleum spills, combustion and traffic. Correlation analysis implied that TPHs residues had an effect on soil environmental quality. This study have important implications for understanding the environmental behavior of petroleum and can provide support for petroleum remediation and risk control.

Remediation of Petroleum Contaminated Tidal Flat Sediments by Co-bioremediation System

ABSTRACT The remediation effects of oil-degrading bacteria, Nereis succinea and Suaeda heteroptera, on oil-contaminated sediments were studied by laboratory pot experiments under simulated conditions of intertidal zone. Three concentrations of oil-contaminated sediments (I: 500 mg/Kg, II: 1500 mg/Kg, III: 3000 mg/kg) and four bioremediation treatment groups (bacteria group, bacteria-N. succinea group, bacteria-S. heteroptera group, bacteria-N. succinea-S. heteroptera group) were set up, and the oil removal efficiency was measured after 15, 30, 45, 60, and 70 days of the experiment, respectively. The results showed that the percent removals of total petroleum content, linear hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs) of each sediment under all bioremediation treatments were significantly higher than those of the control groups (P < .05). The bacteria – N. succinea – S. heteroptera synergistic model performed best, after 70 days of remediation tests, the percent removals of total petroleum content reached 51.9%, 47.8%, and 40.6% under I, II, and III oil concentration conditions, respectively, indicating the biological disturbance caused by N. succinea and the rhizosphere effect of S. heteroptera can effectively promote the oil removal of the bioremediation system. In addition, the oil degradation speed in each bioremediation combination showed an increasing trend in the began month, peaked during 15–30 d period, and then decreased obviously at 30–70 d in all bioremediation treatments. We also found that the synergistic bioremediation models promoted the removal of petroleum linear hydrocarbons and PAHs, and the percent removals of linear hydrocarbons were negatively related to their carbon chain length, and the removal rates of PAHs decreased significantly as the number of benzene rings increases. The above results demonstrated the feasibility of co-bioremediation technology in the remediation of petroleum contaminated tidal flat sediments.

Monitoring hydrocarbon levels during bioremediation by enhanced bio-stimulants using GC-FID

The efficacy of bio-stimulants on the remediation of hydrocarbon polluted soil was assessed using Gas Chromatography with Flame Ionization Detector (GC-FID). The enhanced bio-stimulants were discarded melon pulps, discarded breadfruit pulps and poultry droppings. These were applied to the polluted soil in the ratio of 1:5; the blend was observed for sixty days. Inferring from the chromatographs, the carbon compounds present in the polluted and remediated soils ranged from C12 – C40 with varying concentrations; C12 to C19 were dominant, C9 to C11 were residual with negligible concentrations. The total petroleum hydrocarbon (TPH) of polluted soil was 42,229.73 mg/kg, and the remediated soils were: biodegraded melon pulp - 23,786.3 mg/kg, biodegraded breadfruit pulp - 15,322.82 mg/kg, and chicken droppings, - 7,314.29 mg/kg. The results indicated that TPH of the polluted soil was reduced by 43.67% in sample remediated with biodegraded melon pulp, 63.71% in sample remediated with biodegraded breadfruit pulp, and 82.67% in sample remediated with chicken droppings. Therefore, a decreasing order of the effectiveness of the bio-stimulants is thus: chicken droppings &gt; biodegraded breadfruit pulp &gt; biodegraded melon pulp. The higher remediation potential of poultry droppings is attributable to high nitrogenous content. The study showed that the aforementioned bio-stimulants are effective in remediation of petroleum polluted soil. GC-FID detected the hydrocarbon present and their concentrations in the polluted and remediated soils. GC-FID is preferred to other analytical techniques due to its precision in identification and quantification of hydrocarbon fractions.

A review on biosurfactant producing bacteria for remediation of petroleum contaminated soils.

The discharge of potentially toxic petroleum hydrocarbons into the environment has been a matter of concern, as these organic pollutants accumulate in many ecosystems due to their hydrophobicity and low bioavailability. Petroleum hydrocarbons are neurotoxic and carcinogenic organic pollutants, extremely harmful to human and environmental health. Traditional treatment methods for removing hydrocarbons from polluted areas, including various mechanical and chemical strategies, are ineffective and costly. However, many indigenous microorganisms in soil and water can utilise hydrocarbon compounds as sources of carbon and energy and hence, can be employed to degrade hydrocarbon contaminants. Therefore, bioremediation using bacteria that degrade petroleum hydrocarbons is commonly viewed as an environmentally acceptable and effective method. The efficacy of bioremediation can be boosted further by using potential biosurfactant-producing microorganisms, as biosurfactants reduce surface tension, promote emulsification and micelle formation, making hydrocarbons bio-available for microbial breakdown. Further, introducing nanoparticles can improve the solubility of hydrophobic hydrocarbons as well as microbial synthesis of biosurfactants, hence establishing a favourable environment for microbial breakdown of these chemicals. The review provides insights into the role of microbes in the bioremediation of soils contaminated with petroleum hydrocarbons and emphasises the significance of biosurfactants and potential biosurfactant-producing bacteria. The review partly focusses on how nanotechnology is being employed in different critical bioremediation processes.

Effect of Feedstock Type on Biostimulation Efficiency and Microbial Community Structure during Biochar-Facilitated Remediation of Petroleum Contaminated Soil

This study investigated the effect of plant feedstock– and animal feedstock–derived biochar at 10%w/w and 15%w/w amendment levels on the biostimulation efficiency and the cultivable microbial community in the soil during biochar-facilitated remediation of petroleum contaminated soil using standard techniques. Biostimulation was most effective with the animal-based biochar (ABB) treatment while total petroleum hydrocarbon (TPH) removal was greatest in the plant-based biochar (PBB) amended soil. Observed mean TPH levels on Day 60 ranged from about 7000 mg/kg – 7800 mg/kg for the PBB and 11000 mg/kg – 14000 mg/kg for ABB representing removal levels of roughly 51.0%, 57.7%, 72.4% and 73.7% in 10% ABB, 15% ABB, 10% PBB and 15% PBB amended contaminated soils respectively. The cultivable bacterial diversity for both feedstock types shifted from the combination of Firmicutes, Actinobacteria and Proteobacteria phyla at the onset of the study to predominantly Proteobacteria by the end of the study with a distinct reduction in diversity observed with increasing contact time. The dominant cultivable heterotrophic bacterial isolates were Bacillus spp., Pseudomonas spp. and Staphylococcus aureus for ABB and Pseudomonas spp., Klebsiella pneumoniae and Bacillus spp. for PBB. Amongst the cultivable hydrocarbon utilising bacteria obtained, Klebsiella pneumoniae, Pseudomonas spp. and Enterobacter spp. dominated. There were significant differences in TCHB and CHUB abundance and TPH removal efficiency between PBB and ABB amendments at 95% confidence interval. The study established that application of biochar effectively manages petroleum pollutants in soil by stimulating the proliferation and activities of relevant degradative species.

Using rice husks manure and seaweed extract to optimize the phytoremediation efficiency of guinea grass (Megathyrsus maximus)

Combating environmental degradation through eco-friendly procedures had become a major challenge to environmentalists. This work was done to investigate the possibility of using organic wastes to enhance the phytoremediation of contaminated environments. Virgin soil samples were contaminated with petroleum derivatives (spent motor engine oil, petrol, diesel and kerosene) in a volumetric ratio of 25%:25%:25%:25%. These contaminated soil samples were divided into 7 groups, and were amended with different concentrations and combinations of rice husk manure and seaweed extracts, before guinea grass was transplanted into them. Total petroleum hydrocarbons (TPH) of all the soil samples (virgin, polluted and remediated) were determined in accordance with approved procedures. Findings of the experimental program depicted that rice husk manure phytoremediation enhancer, but combining it with moderate quantity of seaweed extract gave a better result. The TPH concentration in the SAM 2, SAM 3 and SAM 4 soil samples at the end of the experiment declined by 52.23, 61.99 and 70.47%, respectively. While the TPH concentration in the SAM 5, SAM 6 and SAM 7 soil samples, at the end of the experiment declined by 56.91, 66.64 and 61.17%, respectively. The study revealed that extremely high organic materials concentration (as in the case of SAM 7), was detrimental to the remediation process. Findings from this work depicted that proper harnessing of rice husks, which are readily available in Nigeria, can be effectively exploited to augment the remediation of petroleum polluted sites.

The Effect of Soil Particle Sizes on Bioremediation Efficiency of Petroleum Contaminated Soils

ABSTRACT Bioremediation has been proven to be efficient method of cleaning up oil contaminated soils through the application of proper microorganism to contaminated soils. Hence, this research involves the bioremediation of four different types of contaminated soil. The soils were categorized as laterite, sandy soil, clay soil, and loamy soil which are classified technically using American Society for Testing and Materials (ASTM) method as clayey sand, silty sand, clayey sand and poorly graded sand respectively. These soils were contaminated with Bonny light crude oil to the concentration of 33.3 g/l. The soils were inoculated with petroleum remediation microorganisms. Soil samples were taken after 14 and 25 days, and the residual total petroleum hydrocarbon (TPH) was checked using Environmental Protection Agency (EPA) Method 8015. The condition of the soils was kept almost constant during the process by preserving it in an insulated vessel to avoid evaporation of moist or organic gases. The results obtained showed percentage reduction 70%, 69%, 49%, and 26% in hydrocarbon after the period of 25 days in Sand, Laterite, Topsoil and Clay soil respectively. The removal percentage was the highest (70%) for the sandy soil, and the lowest for the clay soil (26%). The result indicate that the particle size distribution of soil affects bioremediation to an extent, since clay with lowest particle size proved more difficult to bio-remediate.

Different Dosage Persulfate Oxidation Coupled with Microbial Remediation of Petroleum Contaminated Soil: Environment Parameters Changes and Microbial Community Response

Different Dosage Persulfate Oxidation Coupled with Microbial Remediation of Petroleum Contaminated Soil: Environment Parameters Changes and Microbial Community Response

Different Dosage Persulfate Oxidation Coupled with Microbial Remediation of Petroleum Contaminated Soil: Environment Parameters Changes and Microbial Community Response

Different Dosage Persulfate Oxidation Coupled with Microbial Remediation of Petroleum Contaminated Soil: Environment Parameters Changes and Microbial Community Response

Advances in the bioaugmentation-assisted remediation of petroleum contaminated soil

Bioremediation is considered as a cost-effective, efficient and free-of-secondary-pollution technology for petroleum pollution remediation. Due to the limitation of soil environmental conditions and the nature of petroleum pollutants, the insufficient number and the low growth rate of indigenous petroleum-degrading microorganisms in soil lead to long remediation cycle and poor remediation efficiency. Bioaugmentation can effectively improve the biodegradation efficiency. By supplying functional microbes or microbial consortia, immobilized microbes, surfactants and growth substrates, the remediation effect of indigenous microorganisms on petroleum pollutants in soil can be boosted. This article summarizes the reported petroleum-degrading microbes and the main factors influencing microbial remediation of petroleum contaminated soil. Moreover, this article discusses a variety of effective strategies to enhance the bioremediation efficiency, as well as future directions of bioaugmentation strategies.