Removal Rate Of Polycyclic Aromatic Hydrocarbons Research Articles

Effects of corn straw on dissipation of polycyclic aromatic hydrocarbons and potential application of backpropagation artificial neural network prediction model for PAHs bioremediation

In order to provide a viable option for remediation of PAHs-contaminated soils, a greenhouse experiment was conducted to assess the effect of corn straw amendment (1%, 2%, 4% or 6%, w/w) on dissipation of aged polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. Backpropagation artificial neural network (BP-ANN) was applied to model the relationships between soil properties and PAHs concentration in soils. The removal rate of PAHs, enzyme activity (catalase and dehydrogenase), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) in soils were investigated to evaluate the dissipation of PAHs under different ratio of corn straw amendment. The present study showed that corn straw amendment apparently accelerated the dissipation of PAHs after incubation of 112 days, especially under 4% and 6% treatments. Compared with non-amended soil, corn straw amendment significantly (p < 0.05) increased the removal rate of low molecular weight (LMW) PAHs and significantly (p < 0.05) enhanced the dissipation of high molecular weight (HMW) PAHs only under 6% treatment. Moreover, corn straw amendment increased activities of catalase and dehydrogenase, concentrations of DOC and MBC in soils, which are beneficial to the degradation of PAHs in soils. The performance of the BP-ANN model was assessed through the root mean square error (RMSE) and determination coefficient (R2). The results indicated that BP-ANN model could provide satisfactory prediction of PAHs concentration in soils during incubation period at R2 and RMSE values of 0.948, 187.4 μg kg−1, respectively. The results indicated that high amendment of corn straw was a potential option for remediation of PAHs-contaminated soils and that the BP-ANN model could successfully provide prompt prediction of PAHs concentration in soils.

Effects and mechanisms of phytoalexins on the removal of polycyclic aromatic hydrocarbons (PAHs) by an endophytic bacterium isolated from ryegrass

Plant-endophyte synergism has been demonstrated to play a key role in the phytoremediation of contaminated water and soil. Phytoalexins, a type of chemical component in the plant apoplast, can be produced by plants in response to stimulation by endophytes. Phytoalexins may have distinct effects on the nutritional and metabolic functions of endophytes; however, direct evidence is not available to prove the effect of phytoalexins on the hydrophobic organic contaminants (HOC)-degradation activity of endophytes. In this paper, three different types of phytoalexins, coumarin, resveratrol and rutin, were selected to study their effect on the removal of polycyclic aromatic hydrocarbons (PAHs) by an endophytic bacterium Methylobacterium extorquens C1. The effects of the three phytoalexins on bacterial sorption and intracellular enzymatic activities were tested to further analyze the mechanism by which the phytoalexins affect the PAH degradation performance of M. extorquens C1. The results showed that the removal rate of PAHs by M. extorquens C1 increased in the presence of low levels of the three phytoalexins. The most effective concentrations of coumarin, resveratrol and rutin were 0.20, 0.15, and 0.25 mg/L, respectively, and the removal rate of PAHs was increased by approximately 18.3–35.0%. At the optimal concentrations, the three phytoalexins significantly promoted the sorption of PAHs by M. extorquens C1, and also enhanced the activities of catechol dioxygenases and dehydrogenase of M. extorquens C1. The positive effect of phytoalexins on both bacterial sorption and intracellular enzymatic activities promotes the overall removal of PAHs from endophytes. These results may deepen our understanding of plant-microbe cooperative mechanisms in the degradation of organic pollutants and provide a new approach for chemically enhanced bioremediation in the future.

Removal of polycyclic aromatic hydrocarbons from different soil fractions by persulfate oxidation

Removal of polycyclic aromatic hydrocarbons (PAHs) from different soil fractions of contaminated soil was investigated by using activated persulfate oxidation remediation in our research. The results showed that the light fraction, which accounted for only 10% of the soil, contained 30% of the PAHs at a concentration of 4352 mg/kg. The heavy fraction contained more high-molecular-weight PAHs, and the total PAH concentration was 625 mg/kg. After being oxidized, the removal rate of PAHs was 39% in the light fraction and nearly 90% in the heavy fraction. Among the different fractions of the heavy fraction, humic acid contained the highest concentration of PAHs, and consequently, the highest removal efficiency of PAHs was also in humic acid. Compared with the light fraction, the heavy fraction has more aromatic compounds and those compounds were broken down during the oxidation process, which may be the removal mechanism involved in the oxidation of high-ring PAHs. Similarly, the enhancement of C=C bonds after oxidation can also explain the poor removal of high-ring PAHs in the light fraction. These results imply that different fractions of soil vary in composition and structure, leading to differences in the distribution and oxidation efficiencies of PAHs.

Dissipation of polycyclic aromatic hydrocarbons (PAHs) in soil amended with sewage sludge and sludge compost

In this study, greenhouse experiments were conducted under the condition of different amendment ratios and planting tall fescue (Festuca arundinacea). The amendment ratios of sewage sludge or sludge compost to soil were of 0, 10, 25, and 50% (w/w). The removal rates of PAH, catalase, and dehydrogenase activities of amended soil and accumulation of PAHs by vegetation were detected to investigate the differences of PAH dissipation in sludge-amended and compost-amended soils. The initial PAH concentrations in three amended soils increased with the more addition of sludge or compost. After 126-day experiment, maximum PAH removal rates were observed in sludge-amended and compost-amended soils with PAH concentration of about 200μgkg-1. And the removal of PAHs showed better efficiencies in compost soil rather than in sludge soil. The more catalase activity and dehydrogenase activity of soil were obtained, respectively, in sludge soil and compost soil. The results indicated that the mechanism of PAH dissipation in two types of amended soils were different. The abundant amount of microorganism dominated PAH dissipation in sludge soils, and PAHs dissipated mainly caused of intense activity of microorganism in compost soils. In addition, PAH accumulation in tall fescue suggested that the transference approach of PAHs was from soil to the roots, and then accumulated in the shoots of tall fescue. It was prone to store up more PAHs in vegetation in the condition of high molar weight of PAHs, more biomass of vegetation, and heavy PAH concentration in soil.

Optimization of Ex-Situ Washing Removal of Polycyclic Aromatic Hydrocarbons from a Contaminated Soil Using Nano-Sulfonated Graphene

Ex-situ soil washing technology offers advantages such as speed and efficiency of remediation and range of application and has been developed to conform with legal requirements and best management practices in USA and some European countries. In this study, nano-sulfonated graphene (SGE) was used as a washing agent to evaluate different processing (washing) parameters for the ectopic leaching removal of polycyclic aromatic hydrocarbons (PAHs) from a coking plant soil. X-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FTIR) were used to analyze the characteristics of the SGE tested. The results showed that SGE had a strong adsorption capacity for PAHs through the role of π-π, H-π, and anion-π interactions. The washing parameters, an SGE concentration of 2 000 mg L−1, a liquid/soil (L/S) ratio of 10:1, and 4 cycles of successive washing, were set to arrive to the optimum condition for achieving more than 80% of PAH removal. Under the optimum condition, the PAH removal rate decreased with increasing ring numbers. After one washing cycle at SGE concentration of 2 000 mg L−1 and L/S ratio of 10:1, the PAH removal rate of the SGE tested was much higher than that of Tween 80 (TW80) or methyl-ß-cyclodextrin (MCD) (P < 0.01). Therefore, SGE is a promising material for the nanoremediation of PAH-contaminated soils.

The role of lipopeptide biosurfactant on microbial remediation of aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soil

Polycyclic aromatic hydrocarbons (PAHs) have been recognised as priority pollutants due to their carcinogenic, mutagenic and teratogenic properties. Bioremediation of PAHs is limited by low bioavailability of soil-bound PAHs due to their low aqueous solubility, high hydrophobicity and strong sorption to soil. The purpose of this study was to investigate the biodegradation enhancement potential of a heavy molecular mass lipopeptidal biosurfactant produced by Bacillus cereus SPL-4 on an aged wood treatment plant soil heavily contaminated with PAHs. In the laboratory scale batch treatments conducted (concentration of 6745.5mgkg−1, sum of 13PAHs) the high molecular weight PAHs removal rate was significantly enhanced in the biosurfactant supplemented microcosms than in the surfactant free controls. In the microcosms supplemented with 0.2 and 0.6% (w/w) lipopeptide, 51.2% of 4-ring and 55% of 5- and 6-ring PAHs; 64.1% of 4-ring and 79% of 5- and 6-ring PAHs were removed respectively, compared to 29% of 4-ring and 25.5% of 5- and 6-ring PAHs removal in the surfactant free control after 64daysof incubation. However, there was no statistically significant change in the degradation rates of low molecular weight PAHs in surfactant amended and surfactant free controls. Fitting the experimental data to two compartment model showed that the biosurfactant addition at 0.2 and 0.6% (w/w) increased the fast degradation fraction to 34.2 and 63% respectively, compared to 6% at the surfactant free controls. The degradation of 5 and 6 ring PAHs was significantly enhanced (p<0.05) in the higher surfactant dosage compared to the lower dosage. The results suggest that biosurfactant assisted degradation by microbial consortium may be a promising practical bioremediation strategy for aged PAH-contaminated soils.

Reducing polycyclic aromatic hydrocarbons content in coal tar pitch by potassium permanganate oxidation and solvent extraction

This study was conducted to assess the feasibility of using potassium permanganate (KMnO4) as an oxidant to reduce 7 carcinogenic polycyclic aromatic hydrocarbons (PAHs) content in two coal tar pitches (CTPs), and to research the oxidation mechanism of KMnO4. It had been observed reduction of major PAHs in CTP after KMnO4 oxidation. The best benzo[a]pyrene equivalency (BaPeq) reduction rate of 82% in n-hexane soluble in a high temperature CTP (HCTP) was achieved with KMnO4 concentration of 0.2M treated for 5h. Specifically, a higher phenanthrene reduction rate (90%) was obtained by using the Soxhlet extraction with n-hexane as solvent on the KMnO4 oxidized HCTP. The single PAH removal rate roughly increases with increasing rings number of PAH, following the order of phenanthrene<fluoranthene<pyrene<benzo[a]pyrene<benzo(b)fluoranthene<indeno[1,2,3-ed]pyrene<benzo[g,h,i]perylene under the same conditions. By using gel penetration chromatography (GPC) and gas chromatography–mass spectrometry (GC–MS), electrophilic substitution reaction was speculated as the oxidation mechanism of CTP by KMnO4.

Microbial Properties and Degradation of Polycyclic Aromatic Hydrocarbons in the Contaminated Farmland Soil with Bioremediation

Degradation of polycyclic aromatic hydrocarbons (PAHs) and microbial quantity were investigated in aged PAHs-contaminated soil in a pot experiment with regrass and alfalfa. After 60 days germination the concentration of total PAHs in soil decreased by 37.57% and 38.41% with the treatment of ryegrass-microbe agent and alfalfa-microbe agent. The processes of ryegrass and alfalfa were 18.72% and 19.34%. The root system promoted the quantity of microbe and the microbial agent was benefit for the PAHs degrading microbe. And there was significant positive correlation between the number of PAHs degrading microorganisms and the removal rate of PAHs in the soil.

Effects of electrokinetic operation mode on removal of polycyclic aromatic hydrocarbons (PAHs), and the indigenous fungal community in PAH-contaminated soil

Electrokinetic remediation is an emerging physical remediation technology for the removal of heavy metals and organic chemicals from contaminated soil. We set up a soil chamber (24 × 12 × 8 cm) with two stainless steel electrodes (12 × 0.5 cm), and a constant voltage gradient of 1.0 v cm−1 or 2.0 v cm−1 was applied to study the effects of unidirectional and altered directional electric field operation modes on the moisture content and pH, the removal rate of PAHs, and the abundance and diversity of indigenous fungi in a PAH-contaminated soil at the Benxi Iron and Steel Group Corporation (N41°17′24.4″, E123°43′05.8″), Liaoning Province, Northeast China. Electrokinetic remediation increased the PAH removal rate, but had less effect on soil moisture content and pH, in comparison with the control. In the 1 v cm−1 altered directional operation, in particular, the PAH removal rate by the end of the experiment (on day 23) had increased from 5.2% of the control to 13.84% and 13.69% at distances of 4 and 20 cm from the anode, respectively, and to 18.97% in the middle region of the soil chamber. On day 23, the indigenous fungal 18S rRNA gene copy numbers and community diversity were significantly higher in a voltage gradient of 1 v cm−1 than in a voltage gradient 2 v cm−1. An altered directional operation was more conducive to the fungal community's uniform distribution than was a unidirectional operation of the electric field. We found the major PAH-degrading fungi Fusarium oxysporum and Rhizophlyctis rosea to be present under EK remediation. We suggest that a 1 v cm−1 altered directional operation could be an appropriate electrokinetic operation mode for PAH removal, and the maintenance of abundance and diversity of the indigenous fungal community.

Effects of Alkyl Polyglucoside (APG) on Phytoremediation of PAH-Contaminated Soil by an Aquatic Plant in the Yangtze Estuarine Wetland

This research evaluated the effects of alkyl polyglucoside (APG), an environment-friendly surfactant, on the removal of anthracene (ANT), phenanthrene (PHE), and pyrene (PYR) from the soil cultivated with Scirpus triqueter, an aquatic native pioneer plant in the Yangtze estuarine wetland, China. Soils spiked with about 200 mg kg−1 of ANT, PHE, and PYR were individually irrigated with 0, 10, 20, 30, 40, 50, 100, and 150 mg L−1 of APG. Plant biomass yields, polycyclic aromatic hydrocarbons (PAHs) removal rates, soil microbial, and soil enzyme activities were quantified after 90 days’ cultivation of Scirpus triqueter. Experiments demonstrated that APG has an ability to facilitate PAHs degradation at appropriate concentrations. The highest removal rate of the PAHs was observed in 40 mg L−1 APG treatment, and the removal rates increased 23, 54, and 52 %, respectively, compared to the non-amended control pots. However, the PAHs removal rate decreased to a certain extent when high concentrations of APG were added. The effect on PAHs removal in the soil could be explained by the changed levels of plant biomass, soil microbial populations, and soil enzymatic activity affected by the APG. The results suggested that the use of Scirpus triqueter combined with APG was an effective means for the phytoremediation of the PAH-contaminated soil. At the same time, APG’s optimal concentration should be determined before the application in the PAH-contaminated wetlands.

Removal of polycyclic aromatic hydrocarbons from municipal sludge using UV light

Abstract This study includes research into using UV light to remove Polycyclic Aromatic Hydrocarbons (PAHs) from municipal sludge. The effectiveness of TiO2 as a photocatalyst on this UV application was also determined. Sludge samples that were taken from an urban wastewater treatment plant (UWWTP) were exposed to UV-C light in a specially designed setup. The total concentration of Σ12 PAH in the sludge, which was 1339 ng g−1 of dry matter initially, decreased by 2–77% after 24 h of UV application. The concentrations of some PAH isomers increased after the UV application, which revealed that isomer transformations could emerge due to the effects of temperature and photodegradation. UV light was found to remove 3-ring light compounds more effectively than 4–6-ring heavy compounds. A total PAH decrease of 77% was achieved by adding an amount of TiO2 equal to 0.5% of the dry weight of the sludge although the removal rate of PAHs from the sludge decreased when the TiO2 dosage was increased. It is possible tha...

Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant Sedum alfredii

Purpose Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study. Materials and methods Soil slightly contaminated by Cd (0.92 mg kg −1 DW) was collected from a vegetable field in Hangzhou and was spiked with two levels (0 and 6 mg kg −1 DW) of Cd and three levels (0, 25, and 150 mg kg −1 DW) of phenanthrene (PHE) or pyrene (PYR). A pot experiment was conducted in a greenhouse using S. alfredii with unplanted controls for 60 days. Shoot and root biomass of plants, dehydrogenase activity (DHA), and microbial biomass carbon in the soilwere measured.Concentrationsof Cdand PAHsin the plant and soil were determined. Results and discussion Elevated Cd level (6.38 mg kg −1 DW) increased S. alfredii growth. The presence of PAHs decreased the stimulatory effects of Cd on plant biomass and Cd concentrations in shoots in Cd spiked soil, thus decreasing Cd phytoextraction efficiency. Cadmium removal by S. alfredii after 60 days of growth varied from 5.8% to 6.7% and from 5.7% to 9.6%, in Cd unspiked and spiked soils, respectively. Removal rate of PAHs in the soil was similar with or without the plants. Removal rate of PYR decreased at the elevated Cd level in the soil. This appears to be due to a decrease in soil microbial activity. This is confirmed by a decrease in DHA, which is a good indicator of soil microbial activity. Conclusions Our results demonstrate that S. alfredii could effectively extract Cd from Cd-contaminated soils in the presence of PHE or PYR; however, both PAHs exhibited negative effects on phytoextraction of Cd from Cd spiked soil (6.38 mg kg −1 DW). S. alfredii is not suitable for remediation of PAHs. The effects of Cd and PAHs concentrations on the removal rate of PAHs appear to be attributed to the changes in microbial activities in the soil.

Effect of soil bacteria on the ability of polycyclic aromatic hydrocarbons (PAHs) removal by Trametes versicolor and Irpex lacteus from contaminated soil

The effect of bacteria represented by indigenous soil microflora or a mixture of soil bacteria Pseudomonas aeruginosa and Rhodococcus erythropolis on fungal growth, extracellular enzyme production and polycyclic aromatic hydrocarbons (PAHs) biodegradation efficiency in soil of white-rot fungi Trametes versicolor and Irpex lacteus was investigated. Both fungi were able to colonize soil. The growth yields measured by ergosterol were about two-fold in I. lacteus after 10 weeks. Laccase was produced in T. versicolor cultures in the presence or absence of bacteria but live bacteria reduced the laccase levels in soil about 5 times. Manganese-dependent peroxidase (MnP) was not detected in T. versicolor cultures. The amounts of MnP and laccase in I. lacteus cultures were not affected by the presence of bacteria. T. versicolor was more efficient in PAH removal for all PAHs tested although its capacity to colonize soil was lower. The removal rates of PAHs by T. versicolor in sterile soil were 1.5-fold, 5.8-fold and 1.8-fold for 2–3-ring, 4-ring and 5–6-ring PAHs, compared to I. lacteus , respectively. I. lacteus showed a low efficiency of removal of pyrene, benzo[a]anthracene and benzo[k]fluoranthene, compared to T. versicolor , whereas chrysene and benzo[b]fluoranthene were degraded by neither fungus. The main effect of the presence of the indigenous microflora or R. erythropolis and P. aeruginosa was a significant decrease of degradation of total PAHs by both T. versicolor and I. lacteus . Weak fungal/bacterial synergistic effects were observed in the case of removal of acenapthylene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene by I. lacteus and acenapthylene by T. versicolor . However, the bacterial effects were different in the two fungi. PAH abiotic losses represented 15 and 21% of the total PAHs after 5 and 10 weeks, respectively; naphthalene and acenaphthene were removed from the soil due to volatilization. ► The bacteria tested did not affect the capability of both fungi to colonise soil and did not influence the fungal growth yields. ► Both fungi were capable to reduce the initial PAH content. ► T. versicolor showed more efficiency in PAHs removal for all PAHs tested, compared to I. lacteus , although its capacity to colonize soil was lower. ► The main effect of the presence of live bacteria in the soil was a significant decrease of PAHs degradation by both fungi.

PAH removal from spiked municipal wastewater sewage sludge using biological, chemical and electrochemical treatments

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied due to their presence in all the environmental media and toxicity to life. These molecules are strongly adsorbed on the particulate matters of soils, sludges or sediments because of their strong hydrophobicity which makes them less bioavailability, thus limiting their bioremediation. Different sludge treatment processes were tested to evaluate their performances for PAH removal from sludge prealably doped with 11 PAHs (5.5mg each PAH kg(-1) of dry matter (DM)): two biological processes (mesophilic aerobic digestion (MAD) and simultaneous sewage sludge digestion and metal leaching (METIX-BS)) were tested to evaluate PAH biodegradation in sewage sludge. In parallel, two chemical processes (quite similar Fenton processes: chemical metal leaching (METIX-AC) and chemical stabilization (STABIOX)) and one electrochemical process (electrochemical stabilization (ELECSTAB)) were tested to measure PAH removal by these oxidative processes. Moreover, PAH solubilisation from sludge by addition of a nonionic surfactant Tween 80 (Tw80) was also tested. The best yields of PAH removal were obtained by MAD and METIX-BS with more than 95% 3-ring PAH removal after a 21-day treatment period. Tw80 addition during MAD treatment increased 4-ring PAHs removal rate. In addition, more than 45% of 3-ring PAHs were removed from sludge by METIX-AC and during ELECSTAB process were quiet good with approximately 62% of 3-ring PAHs removal. However, little weaker removal of 3-ring PAHs (<35%) by STABIOX. None of the tested processes were efficient for the elimination of high molecular weight (> or = 5-ring) PAHs from sludge.

Polycyclic Aromatic Hydrocarbons in the Atmosphere of the Eastern Mediterranean

Atmospheric processes governing the fate of the polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of the Eastern Mediterranean were studied for a two-year period (2000-2001). Atmospheric samples were collected off-shore over the Eastern Mediterranean Sea as well as at a background station in Northeastern Crete, Greece. PAH total concentration varied from 4.1 to 57.2 ng m(-3), with >90% in the gas phase. Gas-to-particle distribution of PAHs was correlated (R2 0.75-0.98, p < 0.001) with their subcooled vapor pressure. Seasonal changes in the total concentration of PAHs were not observed, while the origin of air mass was the dominant factor determining their atmospheric concentration levels. Air masses, originating from central and eastern Europe, were associated with the highest PAH concentrations. Gas-to-particle distribution of sigmaPAHs correlated well (R2 0.75-0.98, p < 0.001) with their subcooled vapor pressure. Tropospheric ozone concentration correlated with the vapor-phase PAH concentration (p < 0.001) but less (p < 0.01) with the particulate PAH concentration. Distribution of volatile PAHs over the Eastern Mediterranean basin was uniform. Conversely, particulate PAH concentrations were higher at sampling sites located close to urban centers. Calculated relative removal rates of PAHs associated with particles were significantly higher than those of volatile members.

Combining anaerobic digestion and ozonation to remove PAH from urban sludge

Combination of anaerobic digestion and ozonation was investigated in order to reduce sewage sludge production. No previous data concerning the impact of such combined process on sludge quality are available. Moreover, control of sludge quality, particularly its concentration in metals or trace organic pollutants is fundamental to limit potential risks owing to sludge land application. Amongst these pollutants, polycyclic aromatic hydrocarbons (PAH) are particularly monitored because of their toxic and carcinogenic properties. Previous results have shown the partial removal of PAH (50%) during anaerobic sludge stabilisation. The aim of this study was to optimise PAH removal by combining anaerobic digestion with ozonation. Ozonation of anaerobically digested sludge improved the PAH removal rate (61%). An additional enhancement (up to 81%) of the PAH removal rate was obtained by the addition of hydrogen peroxide during ozonation. Similar performances were achieved by the use of surfactants, which enhanced PAH bioavailability. Finally, in order to evaluate the feasibility of the combination of the anaerobic digestion with ozonation, the biodegradability of the digested sludge ozonized in presence of surfactants and H 2O 2 was measured.

631 National assessment of long-term use of paraquat for its food and environmental-safety in Korea

Polycyclic aromatic hydrocarbons (PAHs) have been recognised as priority pollutants due to their carcinogenic, mutagenic and teratogenic properties. Bioremediation of PAHs is limited by low bioavailability of soil-bound PAHs due to their low aqueous solubility, high hydrophobicity and strong sorption to soil. The purpose of this study was to investigate the biodegradation enhancement potential of a heavy molecular mass lipopeptidal biosurfactant produced by Bacillus cereus SPL-4 on an aged wood treatment plant soil heavily contaminated with PAHs. In the laboratory scale batch treatments conducted (concentration of 6745.5 mg kg−1, sum of 13 PAHs) the high molecular weight PAHs removal rate was significantly enhanced in the biosurfactant supplemented microcosms than in the surfactant free controls. In the microcosms supplemented with 0.2 and 0.6% (w/w) lipopeptide, 51.2% of 4-ring and 55% of 5- and 6-ring PAHs; 64.1% of 4-ring and 79% of 5- and 6-ring PAHs were removed respectively, compared to 29% of 4-ring and 25.5% of 5- and 6-ring PAHs removal in the surfactant free control after 64 days of incubation. However, there was no statistically significant change in the degradation rates of low molecular weight PAHs in surfactant amended and surfactant free controls. Fitting the experimental data to two compartment model showed that the biosurfactant addition at 0.2 and 0.6% (w/w) increased the fast degradation fraction to 34.2 and 63% respectively, compared to 6% at the surfactant free controls. The degradation of 5 and 6 ring PAHs was significantly enhanced (p < 0.05) in the higher surfactant dosage compared to the lower dosage. The results suggest that biosurfactant assisted degradation by microbial consortium may be a promising practical bioremediation strategy for aged PAH-contaminated soils.