RU2303003C1 - Process of biologically cleaning oil polluted water - Google Patents

Abstract

FIELD: water treatment.

SUBSTANCE: invention relates to biotechnology and environmental protection. Process of invention comprises adding cultures of bacteria Pseudomonas putida to closed water reservoir to be cleaned and culturing bacteria in polluted water in presence of perfluoromethyldecaline. Culturing is conducted under forced aeration of water bulk to be cleaned.

EFFECT: intensified oil destruction process and ensured complete removal of oil pollution from closed water volume.

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Description

The invention relates to the field of biotechnology and ecology, and relates to methods for purifying water from oil pollution using cultures of natural bacteria strains - oil product destructors and can be implemented in various industries, mainly for water purification in closed volumes.

A known method of biological purification of water from oil pollution (see AS USSR No. 1428809, 08/23/1985), in which a culture of bacteria of the genus Pseudomonas is introduced into the purified volume of water and bacteria are cultured in contaminated water in a mixture with a biostimulator, as which use mineral fertilizer - nitroammofosku.

However, this method has a fairly long time of destruction of oil products, because after treatment with a culture of bacteria of the genus Pseudomonas of an open reservoir, the degree of utilization of oil products is 99.2% after 45 days; closed volume - up to 76.8% after 7 days.

A known method of biological purification of water from oil pollution (see RF patent No. 2083508, 09/28/1994), in which a bacterial culture of Pseudomonas putida is introduced into the cleaned closed volume of water and bacteria are cultured in contaminated water in a mixture with a biostimulator, which is used sebacic acid in an amount of (0.08-0.1)% by weight of the degradable oil product - railway grease.

However, it is often difficult to determine the mass of degradable oil products in the purified volume of water in order to add the required amount of sebacic acid and to ensure sufficiently rapid destruction of oil products.

The task was to create a method for biological purification of water from oil pollution in a closed volume using bacteria Pseudomonas putida, in which the purified volume of water serves as a breeding ground for bacteria.

In this case, it is necessary to activate mass transfer processes in a poor mineral nutrient medium to increase the biomass of bacteria by improving the supply of oxygen to the cleaned volume.

The aim of the present invention is to intensify the process of destruction of oil by increasing the yield of biomass of bacteria Pseudomonas putida.

This goal is achieved by the fact that in the method of biological purification of water from oil pollution, in which a bacterial culture of Pseudomonas putida is introduced into the cleaned closed volume of water and cultivation is carried out in a mixture with a biostimulator during forced aeration of the cleaned closed volume of water, and perfluoromethyldecalin is used as the biostimulator in the following the ratio of components, wt.%:

Pseudomonas putida culture 0.1-0.3 perfluoromethyldecalin 2.0-15.0 purified water rest

The essence of the technical solution is illustrated by the following.

A culture of bacteria of the genus Pseudomonas, namely Pseudomonas putida WU 186 (see the journal "Biotechnology", 2004 No. 3, p. 55-62. Bakulin M.K. et al., Is used as a biodestructor of oil products in the proposed method for biological purification of water from oil pollution). "Blue blood" in biotechnology of deep cultivation of bacterial cultures in a synthetic medium with oil).

In order to exclude the formation of an oil film on the water surface and the uniform distribution of oil product components in the water column, the volume of purified water should be under continuous sparging, which leads to forced aeration of the medium volume. Forced aeration provides optimal conditions for accelerating the development of biocenosis and increasing the yield of biomass.

Forced aeration is carried out by bubbling with a flow rate of air volume per medium volume per minute equal to (0.5-1.0) vol./about. × min.

Perfluoromethyldecalin (PFMD), which has a gas transport function, is used as a biostimulant to increase the yield of bacterial biomass. PFMD is added directly to the cultivation medium (water), where petroleum products (oil, fuel oil, etc.) are present as a carbon source for biomass growth. The possibility of adding PFMD directly to the cleaned medium is due to its harmlessness to living organisms.

In addition, PFMD is resistant to aggressive environmental factors (to the action of active chlorine, increased acidity, alkalinity, etc.) and has a density 2 times higher than water, as a result of which, without mixing with water, it sinks to the bottom, which allows it is easy to remove for later use (which is the know-how of the applicant).

The use of PFMD less than 2% does not provide a sufficiently intensive destruction of oil products, because there is a slow process of increasing biomass.

The use of PFMD of more than 15% leads to an excess of oxygen in the medium, which can cause a toxic effect and reduce the yield of biomass.

In addition, the use of PFMD of more than 15% leads to a significant increase in the cost of technology and a decrease in the profitability of the cleaning process.

The method is as follows.

A closed container is filled with water with petroleum products, and then a bacterial culture of Pseudomonas putida is introduced at a rate of at least 10 ⁸ cells / ml and bacteria are cultured in a mixture with a biostimulator, with forced aeration.

Forced aeration is carried out by sparging with an air flow rate of (0.5-1.0) rpm./min. × min. cleaned closed volume of water.

As a biostimulant use perfluoromethyldecalin in the following ratio of components, wt.%:

Pseudomonas putida culture 0.1-0.3 perfluoromethyldecalin 2.0-15.0 purified water rest

As a closed container, classic-type fermenters can be used, equipped with aeration and mixing systems, physical-chemical process control systems and a substrate feeding system, for example, a BIOR-0.25 fermenter.

Examples of the proposed method for the biological treatment of water from oil pollution in an enclosed space are given in the table.

Example 1. A closed container is filled with water and petroleum products, and then a bacterial culture of Pseudomonas putida WU 186 is introduced in an amount of 0.2 wt.%, Which is 2 × 10 ⁸ cells / ml, and bacteria are cultured in a mixture with a biostimulator, with forced aeration.

Forced aeration is carried out by bubbling with an air flow rate (0.5-1.0) vol./about. × min of the cleaned closed volume of water.

The bacterial culture of Pseudomonas putida VU 186 is grown in the following ratio of components wt.%: Bacterial culture Pseudomonas putida VU 186 - 0.2; perfluoromethyldecalin (PFMD) - 5.0; purified water - the rest.

The biomass increase for 96 hours is 67.3 × 10 ⁹ cells / cm ³ in a medium with oil and 43.2 × 10 ⁹ cells / cm ³ in a medium with fuel oil. The degree of decomposition of oil is 81.5%, fuel oil - 21.2%.

Example 2. A closed container is filled with water with petroleum products, and then a bacterial culture of Pseudomonas putida WU 186 is introduced in an amount of 0.1 wt.%, Which is 10 ⁸ cells / ml, and bacteria are cultured in a mixture with a biostimulator, with forced aeration.

Forced aeration is carried out by bubbling with an air flow rate (0.5-1.0) vol./about. × min of the cleaned closed volume of water.

The cultivation of bacteria culture is carried out in an environment with a minimum concentration of components wt.%: Bacterial culture Pseudomonas putida WU 186 - 0.1; perfluoromethyldecalin (PFMD) - 2.0; purified water - the rest.

The application of the proposed method led to a decrease in biomass accumulation by 36.1% in an environment with oil and 16.4% in an environment with fuel oil, the degree of biodegradation of oil by 32.6%, fuel oil by 14.2%, respectively, which may be due to a disadvantage nutrients in the environment.

Example 3. A closed container is filled with water with petroleum products, and then a bacterial culture of Pseudomonas putida WU 186 is introduced in an amount of 0.3 wt.%, Which is 3 × 10 ⁸ cells / ml, and bacteria are cultured in a mixture with a biostimulator, with forced aeration.

Forced aeration is carried out by bubbling with an air flow rate (0.5-1.0) vol./about. × min of the cleaned closed volume of water.

A bacterial culture of the genus Pseudomonas is grown in the following ratio of components wt.%: Bacterial culture Pseudomonas putida WU 186 - 0.3; perfluoromethyldecalin (PFMD) - 15.0; purified water - the rest.

Cell reproduction and disposal of petroleum products is as intense as in example 1, but leads to a significant increase in the cost of technology due to the maximum consumption of a biostimulator.

Example 4. A closed container is filled with water with petroleum products, and then a bacterial culture of Pseudomonas putida WU 186 is introduced in an amount of 0.2 wt.%, Which is 2 × 10 ⁸ cells / ml, and bacteria are cultured with forced aeration without introducing a biostimulator.

Forced aeration is carried out by sparging with an air flow rate of (0.5-1.0) rpm./min. × min. cleaned closed volume of water.

Growing without the addition of perfluoromethyldecalin reduces the accumulation of bacterial biomass by 8.4 times in a medium with oil and 6.9 times in a medium with fuel oil, while the degree of oil utilization decreases by 9.7 times, the degree of utilization of fuel oil by 4.6 times.

Example 5. The cultivation of bacteria Pseudomonas putida VU 186 was carried out according to the conditions of the prototype for 96 hours with the addition of 0.1 wt.% Sebacic acid based on the weight of petroleum products introduced into the water.

Utilization of petroleum products and bacterial growth were less effective than previous examples of the method of biological purification of water from oil pollution with the addition of perfluoromethyldecalin.

The research results are summarized in table.

The table shows that the use of the proposed method of biological purification of water from oil pollution allows to increase the degree of purification of water from oil products in a closed volume in real production conditions, where the intensification of the process of oil destruction is ensured by increasing the yield of bacterial biomass Pseudomonas putida ВУ 186.

Table Biodegradation conditions The concentration of live bacteria after 96 hours, (cells / cm ³ ) × 10 ⁹ The degree of purification,% The amount of hydrocarbon in the medium, g / l Duration of cleaning hours Example 1 Purified water with oil + (0.2 wt.%) Pseudomonas putida ВУ 186 + (5.0 wt.%) PFMD 67.3 81.5






fifty






96 Purified water with fuel oil + (0.2 wt.%) Pseudomonas putida ВУ 186 + (5.0 wt.%) PFMD 43,2 21,4 Example 2 Purified water with oil + (0.1 wt.%) Pseudomonas putida ВУ 186 + (2.0 wt.%) PFMD 31,2 48.9 Purified water with fuel oil + (0.1 wt.%) Pseudomonas putida ВУ 186 + (2.0 wt.%) PFMD 26.8 7.2 Example 3 Purified water with oil + (0.3 wt.%) Pseudomonas putida ВУ 186 + (15.0 wt.%) PFMD 78.9 86.8 Purified water with fuel oil + (0.3 wt.%) Pseudomonas putida ВУ 186 + (15.0 wt.%) PFMD 54,2 24.6 Example 4 (control) Purified water with oil + (0.2 wt.%) Pseudomonas putida WU 186 8.0 8.4 Purified water with fuel oil + (0.2 wt.%) Pseudomonas putida WU 186 6.2 4.6 Prototype Purified water with railway lubrication + (0.2 wt.%) Pseudomonas putida ВУ 186 + (0.1 wt.%) Sebacic acid 29.3 15.8 40 96

Claims (1)

A method of biological purification of water from oil pollution, in which a bacterial culture of Pseudomonas putida is introduced into the cleaned enclosed volume of water and bacteria are cultured in contaminated water mixed with a biostimulator, characterized in that the cultivation process is carried out with forced aeration of the purified volume of water, and as a biostimulator use perfluoromethyldecalin in the following ratio of components, wt.%: bacterial culture of Pseudomonas putida 0.1-0.3 perfluoromethyldecalin 2.0-15.0 purified water rest.