Biosorbent producing for soil cleanupfrom oil pollution

Summary

In this article biosorbent producing for soil cleanup from oil pollution is carried out. Pilot studies of sorbents producing from vegetable origin: peat, sunflower pod, chaff, sawdust of deciduous breeds of trees were conducted. As the result of researches for increase of efficiency of bioremediation of the petrosalted soil the biosorbent on the basis of wood sawdust with the immobilized petrooxidizing microorganisms was offered.

Key words: biosorbent, petrosalted soil, recultivation petrooxidizing microorganisms, bioremediation.

The enterprises of the petrochemical industry are one of sources of formation and accumulation in environment of the petrosalted soil. The toxic components which are a part of the polluted soil such as oil and oil products, and also the considerable content of mineral salts make negative impact on local biocenoses, leading to degradation and a conclusion from an agricultural turn of considerable territories.

Now the problem of recultivation of the petrosalted soil is completely not solved. The existing recultivation methods, such as mechanical, physical and chemical and biological, don't provide fully effective purification of the polluted soil. In this regard development of a complex way of recultivation of the petrosalted soil remains actual.

For the purpose of definition of an optimum sorbent carrier of the immobilized cages of microorganisms vegetable origin sorbents were investigated: peat, sunflower pod, chaff, sawdust of deciduous breeds of trees. Sorbents estimated according to the main physicomechanical (structure-forming) and sorption characteristics, and also on ability of a sorbent to hold in the time of a cage of microorganisms.

For an assessment of efficiency of an immobilization determined quantity of the microorganisms fixed on a surface of the offered sorbents carriers by washout by a known technique. Results are presented in table 1.

Table 1 - Quantity OfhalophilicANM immobilized on sorbents carriers

From the received results it is established that the native galofilnypetrooxidizing microorganisms are immobilized on all studied sorbents, but more on wood sawdust in view of their advanced specific surface. Thus the quantity of the attached microorganisms makes (6±0.6)^107C/g.

As the main criteria for an assessment of structure-forming and sorption properties of sorbents used the following indicators: bulk density, oil capacity and moisture capacity (table 2).

Table 2 - Physicomechanical and sorption characteristics of a sorbent carrier

Considering optimum a ratio of oil capacity and bulk density, and also availability of raw materials to receiving a sorbent, to further researches as a sorbent carrier of microorganisms sawdust of deciduous breeds of trees was taken.

For providing native the halophilic of the petrooxidizingmicroorganisms nutrients it is offered to process previously wood sawdust the water organic extract emitted from excess active silt of the petrochemical enterprises.

For definition of an optimum dose of introduction of extract used sawdust of deciduous breeds of trees with fineness of fractions of 2-5 mm. Saturation of sawdust water organic extract (the content of solid of 150 g/l) was carried out in a mixer with a frequency of rotations of 150 rpm within 15 min.

Efficiency of processing was estimated on a number gain of heterotrophic microorganisms immobilized on the carrier. Results of research are presented in table 3.

Table 3 - Microbiological characteristics of the received sorbents

Apparently from table 3, a dose of introduction of extract with 0,1 to 0,5 ml / (of sawdust) the increase in number is promoted by the heterotrophic microorganisms immobilized on the carrier.

Carrying out drying within 2 hours of the received sorbent at the most optimum temperature for microorganisms - 35-40 °C was a further stage of researches. For sorption characteristics promoted a biosorbent carried out processing of sawdust hydrophobereagents. As ahydrophobisatorthe cetanewas used. Hydrophobization of the carrier with the immobilized microbial flora was carried out at the rate of 15 g/kg. The received samples estimated according to the corresponding sorption characteristics. Results are presented in table 4.

Table 4 - Sorption characteristics of a sorbent

Apparentlyfromtable 4, drying of a sorbent at a temperature of 35-40 °C promotes oil capacity increase, and also decrease in a moisture capacity to 4,54 kg/kg. Additional processing of the carrier paraffin promotes considerable improvement of sorption characteristics (oil capacity - 4,35 kg/kg, a moisture capacity - 2,06 kg/kg).

For increase of efficiency of bioremediation of the petrosalted soil we offer the biosorbent on the basis of wood sawdust with the immobilized petrooxidizing microorganisms processed by water organic extract at the rate of 0,5 ml / (of sawdust) and hydrophobizatedcetane at the rate of 15 g/kg.

Literature

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