MXPA06009641A - Composition and bioremediation method for water polluted by hydrocarbons - Google Patents

Abstract

The invention relates to a novel composition and a novel method for the in situ bioremediation of water polluted by hydrocarbons, in particular oil. To remove, for example, an oil slick that is floating on the surface of a body of water, the new composition can be dispersed in powder form over said oil slick. The inventive composition binds spontaneously with the oil, sinking together with the latter below the surface of the water to finally settle as a fine sediment on the bottom. Within a few hours the toxic hydrocarbons have been eliminated from the water, in such a way that in the case of freshwater, drinking-water quality can be restored. The microbiological degradation takes place in situ. The composition contains silicon carbide and/or silicon dioxide in powder form and preferably additives including granite dust, silica-lime dust and calcium. Said new composition permits a simple, cost-effective bioremediation of oil pollution on the surface of bodies of water. Oil pollution can now be controlled for the benefit of man and his environment, even in underdeveloped and newly industrialised countries, which have previously been neglected for financial reasons.

Description

COMPOSITION AND METHOD FOR THE BIORRECUPERATION OF CONTAMINATED WATER WITH HYDROCARBONS TECHNICAL FIELD The present invention relates to a composition for the bioremediation of water contaminated with hydrocarbons, in particular with crude oil. The invention also relates to a method for the bioremediation of water polluted with hydrocarbons, in particular with crude oil.

STATE OF THE ART The transportation of crude oil and its different fractions from the production sites or from the production centers to the consumer is a risky business, and over large distances it is carried out by oil tankers and pipelines. With the damage to oil tankers in the sea, which happens again and again, millions of tons of crude oil can be released. Large quantities of oil remain in the sea or in inland waters when pipelines leak or are attacked, and have a catastrophic effect on the ecological system. Serious damage to the environment also occurs, however, with oil pollution of a less catastrophic magnitude, as sometimes unfortunately occurs when oil tankers are illegally washed in the sea. Especially in coastal regions oil pollution leads to severe economic and social consequences. With respect to this, this is not the only case of oil-contaminated water release from this oil, as is known for example with the known suction methods, but the one that works best for a simple, final and environmentally satisfactory oil cleaning and the toxic hydrocarbons that are contained in it. So far the following listed measures are applied for the elimination of oil that floats on polluted water. 1. To suck or mechanically collect oil that escaped through specialized vessels and subsequent removal and disposal. 2. Union and / or stabilization of petroleum floating freely with oleophilic or hydrophobic dust or mixtures of fibers on water surfaces, and subsequent collection, removal and disposal. In practice, however, you can suck, remove and possibly dispose of or incinerate only a small part of the oil. In addition, storage and incineration are often carried out without due attention to ecological compatibility, so that this measure in turn encounters considerable resistance. At the same time, sites for the disposal of such critical waste are also absent in many countries, and that removal of freely floating oil is prohibited by law in many countries. A complete set of means and methods for linking oil contamination on water surfaces is known. With respect to the description of these binding agents, in the state of the art, the terms adsorption and absorption often do not differ from each other in a sufficiently unambiguous manner. The accumulation of a sorbed substance on the surface of a sorbent is indicated as adsorption, and the accommodation of the sorbent substance within the sorbent is indicated as absorption. The material to be sorbed therefore has to be indicated as the sorbed material, and the sorbent material as the sorbent or sorption agent, and the material accommodated or bound as sorbate. Nowadays, the absorbent (absorbing agent) that can accommodate as large a volume of oil as possible per volume of binder and that can be sucked from the surface of the water under completely wet conditions is generally suggested for the agglutination of contamination of oil on water. Since most known media with large internal surfaces are hydrophilic or amphiphilic, they must first be processed oleophilically and / or hydrophobically, which requires considerable effort. That agent Absorption based on granules of perlite or see iculite expanded and subsequently siliconized is already known from the DE-2845975 of the year 1980 to be used as an agent to wash oil. In DE-2314616 it is suggested to apply pieces of a cellulose polystyrene foam with a density of 2.24 x 10"2 and 3.21 x 10 ~ 2 g / cm3 as absorbent agent for oily hydrocarbons fluids.The use of polystyrene foam granules also is known from US-3756948. Numerous literature-absorbing agents are known, which have the most varied base materials and additives. Thus, for example, US-3630891 describes hydrophobized wood fibers, and US-3591524 a cellulose-based agent which is hydrophobized with an oil-in-water emulsion containing ammonium or an amine-containing emulsion. The porous material of coconut fiber, which is treated with a hydrophobic oleophilic substance is applied to agglutinate oil contamination of waters in US-4172039. It also suggests filling containers with this material and leaving them adrift on the surface of the water and therefore to absorb the oil, a granulated absorbent agent is described in US-6087301, which separates it from an aggregate of pearlite-gypsum, It contains corn starch and baking powder. It has been demonstrated in practical applications that the mass of agglutinated petroleum absorbing agent floating on the surface of the water is extremely difficult to handle and that the oil absorbed can only be desorbed from the absorbent again only with a very considerable effort. An adsorbent agent based on TiO2 is described in US-6030536, where this adsorbent agent is only applied after the removal of oil contamination from the surface of the water. This highly viscous water-crude oil mixture, which contains up to 90% seawater, is separated in the laboratory or in suitable industrial environments with the adsorbent agent containing Ti02. The crude oil is attached to the adsorbing agent which is subsequently recycled in a multi-stage process. Zr02 and A1203 are also mentioned as adsorbents in the patent document. Since an effective removal of an oil contamination as well as the treatment and subsequent elimination of the often toxic binding agent, crude oil mixtures require a lot of effort and high costs, it is mainly prohibitive in many regions of the world. The result of this is the fact that the initial contamination on the surface of the water with all the negative effects on the marine and limnic ecological systems also leads to the contamination of large coastal regions with enormous costs to humans and the environment. It is actually in developing countries and emerging nations where there is a great need for innovative, cheap and effective means and methods to combat oil pollution on the surfaces of existing waters. Therefore the object of the present invention is to provide a composition and method for the bioremediation of water contaminated with hydrocarbons, in particular with crude oil, which do not have the disadvantages mentioned above.

DESCRIPTION OF THE INVENTION A new solution to the aforementioned problem and the task that derives from it is specified by the present invention as characterized in the patent claims. The new composition and the new method allow a biorecovery in itself. This is to say that crude oil is not only agglutinated, but that biological decomposition in the place is not only accelerated, but often becomes entirely possible in the first place. To combat a layer of oil floating on the surface of the water, it is sufficient to disperse the composition according to the invention on the oil layer. The composition according to the invention has, specifically, the advantageous and surprising characteristic that it combines spontaneously with petroleum, and the sorbate without the formation of large lumps or lumps that are submerged from the water surface to the water bed and settle there like a fine sediment. With the application of the appropriate amounts of the composition according to the invention, heavy and toxic hydrocarbons will be verified in the treated water within a few hours or days. Laboratory tests have yet shown that drinking water quality can be achieved. The oil is degraded into microscopically small parts by means of the new composition according to the invention. The dust particles agglutinate the oil particles by adsorption, arranging themselves around droplets of oil. Due to the higher specific gravity of the powder according to the invention, which is preferably between 2.5 and 3.5, preferably around 3.0, the parts of the oil-dust complex are completely immersed in the respective water bed. The present invention uses physisorption, a special form of adsorption, with which the sorbed matter is bonded by physical forces and not the formation of chemical bonds to the sorbent. The physical forces act there, as a rule, in a non-direct way and have the advantage that the links are reversible. The sorbed matter can thus be released from the sorbent again, which encourages the microbiological degradation of the oil. The submerged oil can also not be separated from the composition according to the invention by means of violent turbulence, and thus it is not dragged to the surface of the water. Since the crude oil is adsorbed on the particles of the composition, the effective surface that is available for attack by the microorganisms that degrade the oil, is greatly increased. The degradation of oil that also becomes possible in this way is greatly accelerated until a complete decomposition of the oil. The microscopically small droplets serve as a substrate for the profuse development of the microorganisms that take part in the degradation. Oil is degraded without any waste within 3 to 4 months, depending on the geological region and the prevailing environmental conditions. The biodegradation or recovery therefore preferably takes place in situ. The difficulty and high costs of sucking oil-binding agent mixtures from the water surface and the subsequent disposal, destruction and reprocessing of this highly problematic waste as mentioned above, leads to the fact that no cleaning measures are taken with the contamination by oil they become superfluous for the invention of in situ decomposition of the toxic hydrocarbon compound. Microorganisms that are suitable for the decomposition of crude oil or other hydrocarbon contamination are added to the composition, and form an important constituent of the product in an advantageous embodiment. The microorganisms are formulated so that their storage capacity and flow capacity are assured. The formulation is preferably carried out in the form of granules or capsules. In particular, national or local regulations for the application of non-native microorganisms can be observed and complied with. Since these can be mixed without any problem in the proper fluid formulation, the constituent microorganisms can be adapted to the regulations that apply to the respective place of application without significant effort. The exact composition of the product in powder form and the grain size of the constituents is preferably adapted to the nature of the oil to be removed. The composition with a specific gravity somewhat higher than 3 g / cm3 is a composition of several rock or natural minerals in powder form. A major essential component of the composition according to the invention is selected from the following group: silicon carbide (SiC), silicon (Si) or silicon dioxide (SiO2). The three substances under normal environmental conditions are inert chemical compounds and have a specific gravity of 2.33 g / cm3 (Si), 2.7 g / cm3 (Si02) and 3.22 g / cm3 (SiC). The grain size of the constituents or individual components of the composition according to the invention. it is preferably between 100 to 600 micrometers. At least more than 50% of the composition should be present as a powder below 400 microns. The following percentages for the previously mentioned individual components (in percentage by weight) have been shown to be favorable or possible: 0-40% silica sand (Si02) 0-60% silicon carbide (SiC) 5-40% granite dust 5-40% silica gel powder (Kiesel alkmehl) 2 to 14% by weight of calcium carbonate (CaC03) can be added as an optional component of the preferred embodiments of the composition. According to a first preferred embodiment, the following composition is preferred within the predefined limits: 20% Si02 20% SiC 40% granite powder 15% silica gel (Kieselkalkmehl) 5% CaC03 The agent specified by the invention according to A preferred embodiment contains silicon carbide with a hexagonal crystal structure. By means of an increase in the portion of granite powder or Si02, preferably in the form of silica sand, a percentage portion of the silicon carbide can be saved or replaced, above all the affinity of the agent according to the invention is increased by means of silica dust. For this reason, the following composition was suggested as a more preferred embodiment within the previously mentioned limits: 40% Si02 40% granite powder 15% silica gel (Kieselkalkmehl) 5% CaC03 As mentioned above, the grain size of the Silicon carbide and / or Si02 as well as that of other applied substances should preferably be between 60 and 600 micrometers. Preferably more than 50% of all the particles would give a size range of less than 400 microns. Since with the application of Si02, which is less expensive but lighter in comparison with SiC, the specific weight of the composition is reduced, in a preferred embodiment it is replaced from 10 to 15% of the granite powder by garnet sand (Granatsand) with a specific weight of 4.1 g / m3. The components described above are composed as follows Component: silicelx powder (Kieselkalk) content of mineral portion in% formula by weight quartz / silicon 25 Si02 calcite 65 CaC03 dolomite 1 CaC03MgC03 pyrite 1 FeS clay (Na, Ca) (Al, Mg) 2 (montmorillonite) Si4O? o (OH) 24H20 complex organic substances or (CxHySz) compounds Component: silicon carbide content of mineral portion in% chemical formula in weight silicon 50 Si carbon 50 Component: silica sand content of mineral portion in% chemical formula by weight quartz / silicon 100 Si02 Component: granite content of mineral portion in chemical formula% by weight quartz / silicon 40 Si02 series of feldspar plagioclase 50 (K, Na, Ca) (AlxSiy02) series of micas (uscovite / biotite) 10 (K, AlxMgy) (F, OH) 2 The following optional components can be applied in additional modalities: Component: Garnet Sand (Granatsand) content of mineral portion in% chemical formula in weight almandin 100 (Fe, Ca, Mg) XA12 (Si04) 3 In an advantageous embodiment, it is replaced from 10 to % of the granite dust by garnet sand.

Test example 1 Normal running water (fresh water) was fixed in the usual salt content of seawater by the addition of sea salt. 20 ml of crude oil was added to one liter of this salt water obtained in a test vessel provided with weak agitation. A lot of agent according to the invention in the composition mentioned above was dispersed on the floating oil essentially on the surface of the salt water (some of the oil however was also distributed in the water in the form of small drops), so that all the The layer of floating oil on the surface of the water was covered with an approximately uniform thin layer of the agent according to the invention. A few seconds immediately after the dispersion of an agent according to the invention with 40% silica sand (grain size 0.2 to 0.3 mm), 40% granite powder, 15% silica gel powder, and 5% of CaCO3, assuming a union with the oil, disappeared from the surface of the water and as a result fell slowly to the bottom of the test vessel like a fine sediment. The water cleared quickly and the oil could no longer be determined optically in the water as well as by the smell, approximately after a day. The oil was completely agglutinated in the sediment.

Test Example 2 Normal running water (fresh water) was fixed to the usual salt content of seawater by the addition of sea salt. 20 ml of crude oil were added to one liter of the salt water thus obtained in a test vessel provided with weak agitation. A lot of agent according to the invention in the aforementioned composition was dispersed on the oil floating essentially on the surface of the salt water (a part of the oil however was also distributed in the water in the form of small drops), so that the layer of floating oil on the surface of the water was covered with an approximately uniform thin layer of the agent according to the invention. A few seconds after the dispersion, an agent according to the invention with 40% SiC, 40% granite powder, 15% silica dust and 5% CaCO3, assuming a union with the oil, disappeared from the surface of the water and as a result fell slowly towards the bottom of the test vessel like a fine sediment. The water cleared quickly and the oil could no longer be determined optically in the water as well as by the smell, immediately after about 1 day. The oil completely clumped in the sediment. A sample (500 ml) of the water treated with the agent according to the invention was moved after 2 days. The water sample was washed via a C18 column and an aliquot of the eluent was examined by traces of oil in an analytical instrumental form. This was done via a chromatographic mass spectrometer system from the Hewlett Packard company. After separation by capillary gas chromatography, masses of 43 and 58 were detected in a selective ionic form. Only 0.05 mg / liter of these masses, ie hydrocarbon or petroleum residues, resulted in the water sample examined. 0.02 were detected. mg / liter of hydrocarbons in the reference sample in salt water, to which no oil was consequently added as well according to the invention. According to the regulations that apply in Switzerland today in relation to the maximum permissible hydrocarbon content, the limit values for the water that is poured into the sewage system is 20 mg / liter, for water that is poured into water of rivers and lakes of 10 mg / liter, and for running waters and river dams of 0.05 mg / liter. A value of 0.01 to 0.05 was assumed for drinking water. Since only 0.05 mg / liter of hydrocarbons was found in the sample examined, this is a quality value comparable to that of drinking water.

Proof of the effectiveness of bioremediation Environmentally hazardous hydrocarbons can be degraded naturally and within a short period of time with the composition according to the invention. The observations that have been made with the internal tests described above, lead to the conclusion that the natural decomposition of the hydrocarbons takes place in an accelerated form under the application of the composition according to the invention, or it becomes possible in first place by means of this. In a bioremediation effectiveness test according to the Protocol of the United States Environmental Protection Agency (EPA) (according to 40 CFR Chapter 1 (7-1-99) Pt, 300 Appendix C, Item 4.0), it was tested by the independent certified testing laboratory Bio-Acuatic Testing in Carrollton, TX, USA, that the treatment with the composition according to the invention (40% SiC, 40% granite powder, 15% silica gel and 5% of CaCO3) of seawater contaminated with crude oil, within 28 days led to a reduction of alkanes by 46.6%, with respect to the untreated control samples. The reduction in the aromatic compounds with the seawater samples contaminated with oil treated with the composition according to the invention was still 86.6% higher than the value of the untreated controls. With the treated samples, a 52.5% reduction in the oil mass occurred compared to the untreated control groups. Regarding the oil that was applied in the trials, this was the case of the Alaska North Slope 521 that can be obtained from the EPA Environmental Verification by the Support Laboratory in Cincinnati, Ohio, USA. The composition according to the invention was deposited on the petroleum surfaces to be treated by means of suitable apparatuses. With tests, a fan has been tested, as for example applied with sand jets. With this, depending on the type and nature of the oil, the individual constituents of the composition according to the invention may vary in location. This means that the composition is not taken to the mixed application site, but instead the individual components are mixed together, preferably by means of a sandblasting fan or bellows. It should be understood that, as the case may be, the mixture may be placed together in a different form for respective application purposes and take into account the nature of the oil to be removed. Apart from submerging and agglutinating the floating oil on a surface of water by means of dispersion on the oil, the agent according to the invention can of course also be used for other specific purposes or in a different way to the described form considering its advantageous properties . For example, means can also be applied for a contamination of the earth with petroleum or with hydrocarbons, to reduce oil or hydrocarbons in water of any kind or in a very general way to improve water quality.

Claims (15)

1. CLAIMS 1. Composition for the bioremediation of water contaminated with hydrocarbons, in particular with oil, characterized in that it contains silicon carbide (SiC) and / or silicon dioxide (Si02) in powder form. Composition according to claim 1, characterized in that it comprises a mineral powder selected from the group: (K, Na, Ca) (AlxSiy? 2) and / or (K, AlxMgy) (F3OH) 2 (AlSi3O? O). Composition according to claim 2, characterized in that the mineral powder is granite powder. Composition according to one of Claims 1 to 3, characterized in that it comprises a mineral powder selected from the group: SiO2, CaCO3, CaCO3MgC03, FeS and / or (Na, Ca) (Al, Mg) 2Si4O? 0 (OH) 24H20. Composition according to claim 4, characterized in that the mineral powder is silica dust or silica sand. Composition according to one of Claims 1 to 5, characterized in that it comprises 20-60% by weight of silicon carbide, 25-40% by weight of granite powder and 5-40% by weight of silica-gel powder. Composition according to one of Claims 1 to 5, characterized in that it comprises 10-40% by weight of silicon dioxide, 25-40% by weight of granite powder and 5-40% by weight of silica-gel powder. Composition according to claim 6, characterized in that it comprises 40% by weight of silicon carbide, 40% by weight of granite powder, 15% by weight of silica-gel powder and 5% by weight of CaCO3. Composition according to claim 7, characterized in that it comprises 40% by weight of silicon dioxide, 40% by weight of granite powder, 15% by weight of silica-gel powder and 5% by weight of CaCO3. Composition according to one of Claims 1 to 7, characterized in that it comprises 20% by weight of silicon carbide, 20% by weight of silicon dioxide, 40% by weight of granite powder, 15% by weight of silica powder and 5% by weight of CaCO3. Composition according to one of claims 3 to 10, characterized in that 10 to 15% of the granite powder is replaced with garnet sand. 12. Composition according to one of claims 1 to 11, characterized in that the grain size of the individual components is between 60 and 600 micrometers, wherein preferably in each case more than 50% of the individual particles are in the region below 400 micrometers Composition according to one of Claims 1 to 12, characterized in that the microorganisms which decompose oil are added in the form of granules or capsules. 14. Method for the bioremediation of water contaminated with hydrocarbons, in. Particular with crude oil, with a composition according to one of claims 1 to 13, wherein the composition as a sorbent is applied directly on the contamination to be removed, so that the hydrocarbons are adsorbed, and immersed with the sorbent, means by which water is released approximately completely from pollution. 15. Method according to claim 14, characterized in that the adsorbed hydrocarbons, in particular the adsorbed crude oil, are decomposed in situ.