26 results about "Hydrocarbon degradation" patented technology

The invention provides a functional aggregate, a preparation method thereof and a self-purification asphalt pavement material. The preparation method of the functional aggregate comprises the following steps: screening residual mud and residue soil, crushing and screening to obtain a raw material, or mixing low-iron-content residue soil and red mud to prepare the raw material; the preparation method comprises the following steps: heating raw materials to 400-550 DEG C, introducing CO2, carrying out heat preservation for 40-120 minutes, then heating to 750-850 DEG C, and carrying out heat preservation for 40-120 minutes, so as to obtain calcined aggregate; soaking the mixed material in a mixed solution containing 0.1-1mol / L FeCl3 for more than 10 hours, and then carrying out hydrothermal reaction at 100-150 DEG C for 4-8 hours to obtain aggregate; and dipping the aggregate in a bacterial liquid containing denitrifying bacteria, petroleum hydrocarbon degrading bacteria and a curing agent, and obtaining the functional aggregate by adopting a vacuum negative pressure dipping method. The material formed by compounding the functional aggregate and the asphalt modifier has the functions of adsorption, catalytic oxidation and biodegradation.

The invention provides a method for rapidly degrading petroleum hydrocarbon in high-salinity oily wastewater, pseudomonas Z1 and achromobacter denitrificans M1 are compounded, an auxiliary liquid is added to obtain a microbial inoculum, the degradation speed of the microbial inoculum to petroleum hydrocarbon and the load tolerance to COD in the wastewater are obviously higher than those of a single strain, and the microbial inoculum has good salinity adaptability. The method has the advantages that in actual wastewater biochemical treatment, flora advantages can be quickly established in a short time under the condition of a small addition amount, the abundance and diversity of microorganisms in a system are effectively improved, and a good petroleum hydrocarbon degradation effect can be achieved within limited hydraulic retention time through continuous operation.

The application discloses a salt-tolerant composite bacterial community, a preparation method thereof and application of the composite bacterial community in high-salt oil sludge remediation. Halomonas venusta The composite bacterial community comprises salt bacillus Acinetobacter calcoaceticus C. acnes CCTCC KB 20081402, and pseudomonas aeruginosa Pseudomonas aeruginosa CCTCC AB 2010174. The application utilizes H. venusta The Ectoine secretion characteristic of the DSM 4743 provides osmotic pressure protection for non-salt-tolerant strains in the composite bacterial community, a Ectoine secretion-transmission-degradation synergistic mechanism is constructed, and the degradation efficiency of petroleum hydrocarbon in a high-salt environment is greatly improved. Experiments show that the petroleum hydrocarbon degradation rate of the composite bacterial community in high-salt oil sludge with a salt content of 35 g / L can reach 43.12% within 7 days. The application is suitable for oil sludge remediation in high-salt environments such as offshore oil fields and saline-alkali soil petroleum contaminated sites, and has important environmental and economic benefits.

The application belongs to the technical field of soil pollutant remediation, in particular to a device for efficiently degrading high-concentration petroleum hydrocarbon in soil, which comprises a feeding module, a conveying module and a thermal desorption module, the conveying module is arranged below the feeding module, the feeding module and the thermal desorption module are connected through the conveying module, together forming a petroleum hydrocarbon degradation device, and the device further comprises a motor and a bracket, the bracket is installed on the surface of the feeding module, a rotating shaft is rotatably connected to the surface of the bracket, and the rotating shaft is driven by the motor; the impurities in the soil can be picked out through the cooperation of the picking rod and the comb plate, so as to avoid the situation that the soil is wrapped in plastic bags, which leads to the reduction of degradation efficiency and the adhesion of the soil to the cylinder wall of the thermal desorption cylinder, and the soil with plastic bags is inconvenient to clean in the later period, the degradation efficiency is improved, and the soil with plastic bags can also avoid causing environmental pollution after backfilling.

The invention discloses bacillus velezensis BZ capable of degrading petroleum hydrocarbon, the name of the strain is BZ, the classification name is bacillus velezensis, the strain is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.31766. The invention further discloses a preparation method of the bacillus velezensis BZ capable of degrading petroleum hydrocarbon. The invention discloses an application of bacillus velezensis capable of degrading petroleum hydrocarbon in degradation of petroleum hydrocarbon. The BZ strain provided by the invention can grow by taking petroleum hydrocarbon as a sole carbon source, can tolerate the low temperature of 5 DEG C and salinity with the concentration of 10%, and can quickly degrade the petroleum hydrocarbon, so that the BZ strain can be widely applied to petroleum degradation. In addition, the strain is simple in culture method and high in tolerant petroleum hydrocarbon concentration, and can be directly used for treating petroleum-polluted water and soil.

The present invention belongs to the fields of genetic engineering and enzyme engineering, and particularly relates to a petroleum hydrocarbon degradation gene and its application. The present invention provides a gene alkane-1-monooxygenase gene that can be used for degrading petroleum hydrocarbons alk B1_3, and the alkane-1-monooxygenase gene alk B1_3 is derived from the petroleum hydrocarbon-degrading bacterium Rhodococcus sp. RHZ01, and the alk nucleotide sequence of B1_3 is shown in SEQ IN NO.1. The present invention constructs a recombinant vector pMBP1- alk B1_3 containing the alkane-1-monooxygenase encoding gene alk B1_3, and expresses it in the prokaryotic host cell Escherichia coli BL21(DE3). Experiments prove that after the gene is expressed in the prokaryotic host cell, the obtained purified monooxygenase has the activity of catalyzing the hydrolysis of alkane substrates, and has great application potential in petroleum hydrocarbon degradation and bioremediation of contaminated soil.

This invention relates to a petroleum hydrocarbon-degrading bacterium and its application, belonging to the field of microbial technology. To address the technical problems in existing petroleum-contaminated soil bioremediation, such as the scarcity of highly efficient degrading strains, low degradation efficiency, and insufficient capacity to handle complex hydrocarbons, this invention provides a petroleum hydrocarbon-degrading bacterium, *Acinetobacter pylori* AFRC34, with accession number CCTCC No:2026007. This strain can use petroleum hydrocarbon organic matter in diesel fuel as the sole carbon source and grows on inorganic salt culture media. It maintains a high petroleum hydrocarbon degradation rate even at a low temperature of 15℃. In an inorganic salt culture medium containing 10,000 mg / L high-concentration diesel fuel at 37℃, the degradation rate reaches 92.46%. The strain and inoculant provided by this invention can efficiently degrade petroleum hydrocarbon pollutants, and are particularly suitable for in-situ bioremediation in cold regions and heavily contaminated sites.

The invention belongs to the technical field of groundwater pollution remediation, and discloses a method for predicting the degradation rate of petroleum hydrocarbon in site groundwater by efficient degrading flora based on complex hydrochemical conditions and a BP neural network. In order to solve the technical problems that chemical conditions of water in underground water in different sites are different, and the composite influence of the chemical conditions on the remediation effect of the efficient degrading flora is difficult to predict, a data set of the petroleum hydrocarbon degradation rate, the water body dissolved oxygen, the water temperature, the salinity, the NH3-N concentration and the remediation time is constructed through laboratory simulation. Secondly, a BP neural network model for predicting the degradation rate of petroleum hydrocarbon in underground water through dissolved oxygen in water, water temperature, salinity, NH3-N concentration and restoration time is established, and it is proved that the model has good prediction capacity and can effectively predict the degradation rate of the petroleum hydrocarbon by flora under different underground water chemical conditions. A reference is provided for predicting the effect of repairing petroleum hydrocarbon in underground water by microorganisms.

The application discloses a kind of Rhodococcus pyridinivorans, microbial inoculum and its application in petroleum hydrocarbon contaminated soil remediation, and relates to the field of microbial technology.The Rhodococcus pyridinivorans is preserved in China General Microbiological Culture Collection Center on December 11, 2023, and the preservation number is CGMCC NO.29278.The application also discloses the application of the strain in soil pollution bio-pile remediation.The strain has a significant removal effect on petroleum hydrocarbons in soil, and the petroleum hydrocarbon degradation rate of the bio-pile using the strain is 63.25% in 14 days, and the petroleum hydrocarbon degradation rate is 82.21% in 14 days after adding carbon source, and the strain can resist 5000mg / kg of petroleum hydrocarbon.The Rhodococcus pyridinivorans and the microbial inoculum made of the strain provided by the application can be used for bio-pile treatment of high-concentration petroleum hydrocarbon contaminated soil, and have the advantages of green, safe, efficient and good application prospect.

The invention discloses a composite biological stimulation agent for stimulating activity of a petroleum hydrocarbon degrading enzyme, which comprises the following components in parts by weight: 5 to 8 parts of KNO3, 5 to 10 parts of FeSO4, 1 to 8 parts of MnSO4, 1000 parts of rhamnolipid and 20 parts of succinic acid. The method has the beneficial effects that the spanning of an in-situ bioremediation technology of the petroleum-polluted underground water from experience to quantification and mechanization is promoted, and the method has important theoretical value and engineering application prospect. The restoration efficiency is improved in magnitude, and the petroleum hydrocarbon degradation rate within 7 days is improved to 75% from 30% under the natural attenuation condition.

The invention discloses a petroleum hydrocarbon degradation complex microbial inoculant as well as a preparation method and application thereof, and relates to the technical field of petroleum hydrocarbon degradation, the petroleum hydrocarbon degradation complex microbial inoculant is prepared by taking magnetic phosphorus-containing biochar as an immobilization carrier and loading composite petroleum hydrocarbon degradation bacteria on the surface of the magnetic phosphorus-containing biochar; wherein the magnetic phosphorus-containing biochar is prepared by firstly activating and pyrolyzing biomass shell powder and potassium feldspar powder through phytic acid to obtain phosphorus-containing biochar, and then coprecipitating the phosphorus-containing biochar and ferric salt; the composite petroleum hydrocarbon degrading bacteria are prepared by mixing bacterial suspensions of at least two of the following petroleum hydrocarbon degrading bacteria in an isovolumetric manner: pseudomonas, bacillus, micrococcus, lactobacillus, candida albicans or alcaligenes. The petroleum hydrocarbon degradation composite microbial agent provided by the invention has an excellent degradation effect on petroleum hydrocarbon, can be used in a heavy metal / petroleum hydrocarbon composite polluted soil environment, and has a good application effect.

The invention relates to the field of environmental governance and bioremediation, in particular to stenotrophomonas sp. BRS7-2 for degrading petroleum hydrocarbon in a saline-alkali environment and application, the stenotrophomonas sp. BRS7-2 is preserved in China Center for Type Culture Collection on March 20, 2025, and the preservation number is CCTCC NO: M 2025545; the strain can produce glycolipid surfactants, and can degrade crude oil, toluene, isooctane, n-hexadecane, naphthalene, phenanthrene, pyrene and benzopyrene. The strain has the characteristic of saline-alkaline tolerance, and can degrade 71.01% of petroleum hydrocarbon under the conditions that the pH is 7.4 and the crude oil concentration is 3%; under the high saline-alkaline conditions that the pH is 8.0, the NaCl concentration is 7.5% and the crude oil concentration is 3%, 54.16% of petroleum hydrocarbon is degraded, by means of the excellent saline-alkaline tolerance and efficient petroleum hydrocarbon degradation performance, a powerful tool is provided for treatment and efficient remediation of saline-alkaline and petroleum polluted environments, and the huge potential of large-scale application in the field of ecological remediation is shown.

The invention relates to the field of preparation of a multi-shell structure slow-release medicament, and discloses a preparation method of a multi-shell structure slow-release medicament for repairing petroleum-polluted underground water, which comprises the following steps: 1, preparing a nutrition matrix: the nutrition matrix comprises the following components in parts by weight: 100.0 to 150.0 parts of NaH2PO4, 500.0 to 600.0 parts of K2HPO4, 50.0 to 100.0 parts of NH4H2PO4, 50.0 to 100.0 parts of NaNO3, 10.0 to 20.0 parts of CaCl2, 50.0 to 100.0 parts of MgSO4. 7H2O, 5.0 to 15.0 parts of FeSO4. 7H2O and 0.1 to 0.5 part of VB12; and 2, preparing the slow-release medicament: preparing the slow-release medicament with a single-layer shell structure, preparing the slow-release medicament with a double-layer shell structure and preparing the slow-release medicament with a three-layer shell structure. The slow-release agent has the beneficial effects that petroleum hydrocarbon in underground water can be efficiently degraded, and the petroleum hydrocarbon degradation effect is improved by 40% or above when the slow-release agent stimulates indigenous microorganisms to act for 10 days under experimental conditions.

The invention belongs to the technical field of oil field oil-containing polluted soil treatment, and relates to a self-heating soil petroleum hydrocarbon degradation treatment agent which comprises denitrifying bacteria, a microbial agent, a microbial degradation nutrient solution, nitrate, ammonium salt and expanded vermiculite. The adding amount of the denitrifying bacteria is 1%-3% of the mass of the petroleum hydrocarbon polluted soil; the microbial agent is petroleum hydrocarbon degrading bacteria, and the addition amount of the microbial agent is 1-3% of the mass of the petroleum hydrocarbon polluted soil; the mass ratio of the sodium nitrate to the denitrifying bacteria is (0.5-0.7): 1; the mass ratio of ammonium chloride to sodium nitrate is (1-1.5): 1; the adding amount of the expanded vermiculite is 2%-3% of the mass of the petroleum hydrocarbon contaminated soil. The invention further discloses a using method of the microbial agent, the denitrifying bacteria serve as a heat production initiator, nitrate is slowly decomposed into nitrite, the whole heat production reaction is changed into a controllable reaction by controlling slow production of reactants of the heat production reaction, and smooth proceeding of microbial treatment of the oil-containing contaminated soil is guaranteed.

This invention discloses a method for preparing a dual-emulsion sustained-release agent for remediating petroleum-contaminated groundwater, belonging to the field of petroleum pollution control. The method includes preparing a nutrient matrix, preparing a dual-emulsion nutrient sustained-release agent, and preparing an outer shell structure. The specific steps for preparing the dual-emulsion nutrient sustained-release agent are as follows: Step 1, obtaining an inner aqueous phase W1; Step 2, obtaining an experimental oil phase O; Step 3, stirring to form a W1 / O type emulsion; Step 4, obtaining an outer aqueous phase W2; Step 5, obtaining the dual-emulsion nutrient sustained-release agent. The specific steps for preparing the outer shell structure are as follows: Step 1, heating to form a gelling agent; Step 2, the ratio of the gelling agent to W1 / O / W2 is 5:1; Step 3, water bath heating; Step 4, solution separation; Step 5, obtaining a boric acid solution; Step 6, forming spherical structures in the solution; Step 7, obtaining the dual-emulsion sustained-release agent. Beneficial effects: It can efficiently degrade petroleum hydrocarbons in groundwater, improving the petroleum hydrocarbon degradation effect by more than 40%.

This invention provides a microbial community with petroleum-degrading capabilities, comprising *Gordonia sp. Strain C1*, *Cellulosimicrobium sp. Strain C3*, or both, wherein *Gordonia sp. Strain C1* and *Cellulosimicrobium sp. Strain C3* are CGMCC No. 25708 and CGMCC No. 25709, respectively. Using the microbial community and culture formula provided by this invention, the community achieves a petroleum hydrocarbon degradation rate greater than 60% in a petroleum degradation system with a petroleum content of 60,000-100,000 mg / L, with a maximum degradation rate exceeding 85%. This community can be applied in petroleum pollution treatment processes centered on microorganisms, contributing to the ecological remediation of petroleum-polluted environments and showing broad application prospects in the ecological restoration of petroleum-polluted soil or water bodies.

The invention provides a compounding method and application of a group of cadmium-resistant petroleum hydrocarbon degrading flora, belongs to the technical field of microorganisms, can realize effective degradation of petroleum hydrocarbon, can adapt to a cadmium-containing degrading environment, and further can realize effective degradation of the petroleum hydrocarbon in the cadmium-containing environment. The method comprises the following steps: preparing a pseudomonas oleovorans solution and a pseudomonas monteilii solution, and performing cadmium-tolerant domestication through a petroleum hydrocarbon degradation culture medium to obtain a domesticated pseudomonas oleovorans solution and a domesticated pseudomonas monteilii solution; and finally compounding the two bacterial solutions to obtain the cadmium-resistant petroleum hydrocarbon degrading flora.

This invention belongs to the field of groundwater pollution remediation technology and discloses a method for predicting the degradation rate of petroleum hydrocarbons in groundwater by highly efficient degrading microbial communities based on complex hydrochemical conditions and a backpropagation (BP) neural network. Addressing the technical challenge of predicting the remediation effect of highly efficient degrading microbial communities due to differences in hydrochemical conditions and their combined influence in groundwater at different sites, this invention constructs a dataset of petroleum hydrocarbon degradation rates in relation to dissolved oxygen, water temperature, salinity, NH3-N concentration, and remediation time through laboratory simulations. Furthermore, a BP neural network model is established to predict the degradation rate of petroleum hydrocarbons in groundwater using dissolved oxygen, water temperature, salinity, NH3-N concentration, and remediation time. The model demonstrates excellent predictive ability and can effectively predict the degradation rate of petroleum hydrocarbons by microbial communities under different groundwater hydrochemical conditions, providing a reference for predicting the effectiveness of microbial remediation of petroleum hydrocarbons in groundwater.

The invention relates to the technical field of soil and groundwater pollution remediation and bioengineering, and discloses a complex microbial inoculant with a polycyclic aromatic hydrocarbon and petroleum hydrocarbon degradation function and application. The invention relates to a compound bacterial agent, which comprises Pseudomonas geniculata, Microdochium sp. And Bacillus velezensis, and is characterized in that the compound bacterial agent comprises Pseudomonas geniculata, Microdochium sp. And Bacillus velezensis, and the compound bacterial agent comprises Pseudomonas geniculata, Microdochium sp. And Bacillus velezensis. The composite microbial agent provided by the invention has high degradation efficiency on polycyclic aromatic hydrocarbon and petroleum hydrocarbon combined pollution, can be used for repairing polycyclic aromatic hydrocarbon and petroleum hydrocarbon combined pollution soil or polycyclic aromatic hydrocarbon and petroleum hydrocarbon combined pollution underground water, and has a good application prospect in green and sustainable repairing of petrochemical pollution sites.

The invention belongs to the technical field of oily sludge bioremediation, and particularly relates to a petroleum hydrocarbon degradation composite flora and application thereof, and the composite flora comprises P.megatherium OS-A1 and Bacillus tropicalis OS-D5; the P.megatherium OS-A1 is preserved in the China Center for Type Culture Collection on June 17, 2025, and the biological preservation number of the P.megatherium OS-A1 is CCTCC NO: M 20251408; the bacillus tropicalis OS-D5 is preserved in the China Center for Type Culture Collection on June 17, 2025, and the biological preservation number of the bacillus tropicalis OS-D5 is CCTCC NO: M 20251409. According to the invention, the technical problems of poor flora stability and incomplete metabolic substrate coverage in the prior art are solved, the coverage of full carbon chain degradation is realized, the limitation of a single strain on specific hydrocarbon degradation is avoided, and a breakthrough solution is provided for complex petroleum pollution remediation.

The application provides a method for rapidly degrading petroleum hydrocarbon in high-salt oil-containing wastewater, adopts Pseudomonas Z1 and denitrifying achromobacter M1 for compounding, adds auxiliary liquid to obtain a bacterial agent, the degradation speed of the bacterial agent on petroleum hydrocarbon and the load tolerance of the bacterial agent on COD in wastewater are obviously higher than those of single bacterial species, and the bacterial agent has good salinity adaptability. In actual wastewater biochemical treatment, the bacterial agent can rapidly establish the bacterial community advantage in a small amount and a short time, effectively improves the microbial abundance and diversity in the system, and can achieve a better petroleum hydrocarbon degradation effect in a limited hydraulic retention time in continuous operation.

The invention belongs to the technical field of remediation of soil pollutants, and particularly relates to a device for efficiently degrading high-concentration petroleum hydrocarbon in soil, the device comprises a feeding module, a conveying module and a thermal desorption module, the conveying module is arranged below the feeding module, the feeding module is connected with the thermal desorption module through the conveying module, and the thermal desorption module is connected with the feeding module through the conveying module. The petroleum hydrocarbon degradation device further comprises a motor and a support, the support is installed on the surface of the feeding module, the surface of the support is rotationally connected with a rotating shaft, the rotating shaft is driven by the motor, a ram is matched with a comb plate, impurities in soil can be picked out, the situation that the soil is wrapped by a plastic bag is avoided, and the degradation effect is good. The problems that the degradation efficiency is reduced and the plastic bags are adhered to the roller wall of the thermal desorption roller and the later cleaning is inconvenient are solved, the degradation efficiency is improved, and meanwhile, the pollution to the environment after the soil with the plastic bags is backfilled can be avoided.

The invention relates to the technical field of oilfield chemistry, in particular to bacillus subtilis zymophyte liquid, a microbial composite nano bactericide and a preparation method thereof, and the preparation method of the bacillus subtilis zymophyte liquid comprises the following steps: culturing a bacillus subtilis strain in a culture medium to obtain the bacillus subtilis zymophyte liquid; wherein the culture medium is a fermentation culture medium or a hydrocarbon degradation culture medium. Fermentation bacteria liquid of the bacillus subtilis strain contains lipopeptide biosurfactants, can play roles of dispersing agents, stabilizing agents, blocking agents, reducing agents and the like in metal nanometer synthesis, can inhibit excessive growth of nanometer particles and prevent the nanometer particles from being gathered / condensed in colloid synthesis, and has the capacity of inducing tiny changes of the nanometer particles. The microbial composite nano bactericide is prepared on the basis of the zymophyte liquid, AgNPs in the microbial composite nano bactericide is small in particle size and good in dispersity and stability, and harmful florae such as sulfate reducing bacteria in the oil field environment can be well inhibited.

The invention discloses a mud flat petroleum hydrocarbon degradation immobilized pellet as well as a preparation method and application thereof. The immobilized pellet for degrading the mud flat petroleum hydrocarbon comprises micro-spheres embedded with petroleum composite degrading bacteria and a coating shell coated on at least one micro-sphere, wherein the coating shell is provided with a pore structure; wherein the microspheres are prepared from an embedding agent, a cross-linking agent and the petroleum composite degrading bacteria; the petroleum composite degrading bacterium is prepared from the following components: SI-JHS, C04-38, Trust-DM21 and SJDQ-112, and is characterized in that the Trust-DM21 and the SJDQ-112 are used as raw materials The embedding medium comprises sodium alginate, polyvinyl alcohol and activated carbon; raw materials for preparing the coating shell comprise chitosan and calcium carbonate; the pore structure on the coating shell is generated through reaction in inorganic acid. The immobilized pellet can degrade petroleum hydrocarbon, solves the problem of petroleum pollution, can realize industrial application, and provides an efficient and feasible solution for petroleum hydrocarbon pollution abatement of mud flats.

A rim seal for a flammable liquid storage tank is provided. The rim seal forms a vapor impermeable barrier with passive fire-suppressing capabilities provided by layers of buoyant members that suppress flammable vapors to prevent fires. The buoyant and fire-retardant members are contained within a closed flexible membrane. The closed flexible membrane contains one or more layers of the buoyant members. The closed flexible membrane and the buoyant members therein extend across the gap formed between an outer circumferential edge of a floating roof and the inner wall of the liquid storage tank. The buoyant members form the layers under the influence of gravity. The buoyant members are formed from a material which is resistant to hydrocarbon degradation, and which is flame retardant and vapor suppressing. The layers of the buoyant members form a passive fire protective barrier between the flammable liquid in the storage tank and the atmosphere.

The invention belongs to the crossing field of environmental engineering, soil remediation and ecological restoration, and relates to a petroleum hydrocarbon degrading bacterium immobilized composite material with pH self-buffering and long-acting slow-release functions and application of the petroleum hydrocarbon degrading bacterium immobilized composite material in contaminated soil remediation and plant synergy. According to the composite material disclosed by the invention, iron alginate gel is used for embedding charcoal to form a composite carrier, and a petroleum hydrocarbon degrading flora is specifically fixed. The composite material disclosed by the invention can be used for efficiently degrading petroleum hydrocarbon; organic acid impact in petroleum hydrocarbon degradation can be effectively resisted, and the microenvironment is stabilized; the long-acting slow release of the petroleum hydrocarbon degrading bacteria is realized, and the bacteria become dominant bacterial communities in the later period of remediation; meanwhile, as a slow-release carbon-based fertilizer and an iron source, the carbon-based fertilizer and the iron source cooperate with functional bacteria metabolites, so that the activity of key enzymes such as soil dehydrogenase and FDA hydrolase is remarkably improved, plant growth is promoted, and systematic remediation integrating single degradation to degradation-improvement-growth promotion is achieved. The material is simple and convenient to prepare, and a new technology is provided for green and sustainable remediation of petroleum hydrocarbon pollution.