Method for bio-assisted treatment of hydrocarbon contaminated soil

Provided is a process of treating a hydrocarbon-contaminated soil/gravel using a blend of germs by adding a first microbe chosen from the group consisting of Pseudomonas aeruginosa strain IOCX, Pseudomonas aeruginosa strain IOC DHT and mixes thereof into a hydrocarbon-contaminated soil/gravel to release the hydrocarbon; also including another microbe chosen from the group consisting of Pseudomonas putida strain IOC5al, Pseudomonas putida strain IOCRl, Bacillus subtlis and a mixture thereof to degrade the released hydrocarbon.


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The production, processing, storage, transportation, in addition to accidental spillage of petroleum and petroleum distillates has led to the launch of hydrocarbon to the surroundings. This has caused large number of pollutedsites and tremendous volumetric amounts of soil, which have been contaminated with poisonous substances. Soil contamination can cause extensive damage to the ecosystem by accumulating in the tissue of plants and animals and by causing deaththereto and/or mutation into the progeny thereof. Such pollution can also pose a serious health threat to individuals, and, in extreme situations, can render the contaminated region unsuitable for human habitation.

The hydrocarbon-contaminated soil/storage pits are usually treated by protected landfill, incineration, indirect thermal treatment, aeration, venting, air sparging and traditional bioremediation. Sludge saved in storage pits and oilcontaminated soil using large amount of stones/gravels/coarse material and loose flowing water can’t be treated with these methods. In such regions the hydrocarbon oil present in sediment doesn’t remain bio-available for microbial action and oil remainpartitioned involving water stage and strong soil/gravel particles.

There are lots of hydrocarbon-contaminated sites like close to the riversides, low-lying locations, in the rain likely areas where hydrocarbon contaminated land stay from the slurry form and water stays in free flowing conditions on the surface. Thesesites cannot be treated by conventional procedures. The problem becomes much pronounced when such water-flooded hydrocarbon contaminated region includes large gravels and rocks besides dirt.

To get a successful remedy of oil-contaminated dirt the discharge of hydrocarbon adsorbed on solid dirt particles/gravel surface is essentially required. Various surfactants of biological or chemical origin are having the capability to discharge oilfrom sediments. But, chemical surfactants owing to their toxicity towards germs, especially hydrocarbon degrading microbes and other adverse environmental impact are not used commonly and moreover, chemical surfactants are present lesseffective for sustained discharge of petroleum. Improved hydrocarbon discharge and degradation along with purified biosurfactant is reported in previous art (Rahman et al., Bioresource. Technology, 90, 159-168. 2003; Kuyukina et al., EnvironmentInternational., 31,155-161, 2005). However, for discipline bioremediation application based on bioaugmentationas well as the biosurfactant-producing bacteria might be beneficial and more practical than exogenously including purified biosurfactant.

Dean and co-workers (Journal of Environmental Quality 30:1126-1133 (2001)) analyzed phenanthrene biodegradation by co-culture of phenanthrene degrading germs and germs having surfactant-producing strains in Fallsington sandy loam soilmicrocosms and aqueous medium, separately. The co-culture of contaminant-degrading and surfactant-producing germs caused the total enhancement of phenanthrene degradation.


Van Hamme and Ward, (Appl Environ Microbiol.

October; 67(10):4874-9, 2001.) Analyzed the physical and metabolic interactions between Rhodococcus sp. strain F9-D79 and Pseudomonas sp. Strain JA5-B45 were analyzed during development on Bow Rivercrude oil at 250-ml Erlemneyer flasks containing 50 ml of medium and reported that a slight enhancement in TPH elimination by the coculture compared to individual bacterium. From the co-culture Rhodococcus sp. Strain F9-D79 forms excellent, though transient, crudeoil-water emulsions between 24 and 48 h of incubation. Pseudonmonas sp. Strain JA5-B45 does not emulsify oil but does efficiently degrade crude oil.


U.S. Pat.

No. 3,871,956 includes a method for cleaning accidental oil spills on water or in soil. The method of this patent doesn’t use oxygen or temperature controls and isn’t a self-perpetuating process.


U.S. Pat.

No. 5,035,537, discloses a method for treatment of soil, porous stone and similar substance contaminated by petroleum, hydrocarbon and volatile organic compounds and includes the steps of gathering the contaminated soil, disbursing ituniformly within an impervious horizontal surface to a depth of four to six inches, treating it using an emulsifying agent and allowing the emulsifying agent to float through the soil and volatilize the hydrocarbon and natural substances from the soil.


U.S. Pat.

No. 5,055,196 reveals a procedure for treating soil or sludge to remove contaminants in contact with the soil or sludge. More particularly, this technique relates to a process by which inorganic contaminants, such as metal or metalsalts, or organic contaminants, such as PCBs, are removed from water-wet dirt and sludge.


U.S. Pat.

No. 5,059,252 reveals a method for on-site bioremediation of soils contaminated with petroleum derived hazardous wastes. This way of improving bioremediation contains the step of applying a cationic ion exchange resin to thecontaminated dirt at an amount sufficient to promote growth of organisms capable of degrading the hazardous waste.


U.S. Pat.

No. 5,427,944 teaches a procedure for biodegrading polycyclic aromatic hydrocarbon contaminants employing a combined bacteria civilization of Achromobacter sp. and Mycobacterium sp. And nutrient. The mixed bacteria civilization was used for insitu or ex situ bioremediation of contaminated soil, or in some of various conventional bioreactors to treat contaminated liquids such as landfill leachates, groundwater or industrial effluents.


U.S. Pat.

No. 5,453,133 describes a procedure for eliminating contaminants, like hydrocarbons, from soil. The process involves contacting the contaminated soil with an appropriate solvent for the contaminant, at the existence of an bridging liquid,which is immiscible with the solvent, while agitating. The quantity of the bridging liquid and also the level of overtraining are balanced to control the particle size of this substantially contaminant-and solvent-free soil agglomerates so formed.


U.S. Pat.

No. 5,494,580 relates to a method for decontamination of a hydrocarbon-polluted environment by using specific bacterial compositions.


U.S. Pat.

No. 6,057,147 discloses an apparatus and process for enhanced bioremediation of hydrocarbons removed from a contaminated object. The apparatus and procedure promote continuous microbial bioremediation of hydrocarbon contaminants in aself-propagating manner whilst cleaning the solution and filtering sediment without generating an environmentally dangerous waste route. The cleaning solution contains germs of the genus Achromobacter, Actinobacter, Hlcaligene; Arthrobacter,Bacillus, Nocardia, Flavobacterinm, Pseudoinonas and combinations thereof.


U.S. Pat.

No. 6,652,752 discloses method for the biodegradation of an oil-based sludge comprising a combination of oil hydrocarbons. The system includes forming an aqueous solution at a reactor of an oil-in-water emulsion of the oil-basedsludge, bacterial culture and nutrition for its bacterial culture, the bacterial culture with the capability to grow petroleum hydrocarbons as sole carbon source and also having been isolated from a hydrocarbon contaminated soil or hydrocarbon-containingsludge or other environments rich in hydrocarbon degrading bacteria, keeping the aqueous solution under aerobic conditions at the reactor at a temperature of 10. degree. C. for a time period sufficient to decrease the quantity of hydrocarbonby at least 25%, and discharging aqueous solution with a reduced quantity of hydrocarbons in the reactor.

The United States Patent Application 20020187545 reveals a procedure for bioremediation of hydrocarbon-contaminated waste utilizing corn substance. The hydrocarbonaceous contaminant is contacted with the corn substance in the presence of nutrientsand bacteria effective for bioremediation.

The present invention teaches the art to decontaminate effectively the oil-contaminated soil using soil with free flowing water over it or in soil-water slurry form and the hydrocarbon is either adsorbed in soil/gravel particles or existing inthe water-soil interface using a mix of compounds that are novel.

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