Use of oil chemistry production wastes by treatment of water and soil from oil products

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Azerbaijan State Oil and Industry University

Use of oil chemistry production wastes by treatment of water and soil from oil products

Abstract

For determination of the efficiency of the oil biosorbent, recived on base of carbonizate - waste of pyrolysis of excess sludge of oil chemical enterprice and also on base of hydrocarbon-oxidizing microorganisms, separated from oil - contaminated soil, the experimental researchs were carried out.

It have been determined that by comparison with carbonizate, use of biosorbent didn't allow to increase efficiency of water treatment. The experimental research by bioremediation of the oil-contaminated soil shown that efficiency of soil treatment by help of the received biosorbent in 1,6 times higher by comparison with use of carbonizate and in 1,7 times higher by comparison with traditioval method treatment.

Key words: biosorbent, biological treatment of waste water, bioremediation of the oil-contaminated soil.

During the extraction, transportation and profirst of all, the hydro- and lithosphere are polluted. Ancessing of oil there are emergencies and technological nual losses from produced oil range from 2 to 5% [1]. losses arise, as a result of which the environment and A promising direction for the purification of oil is a biotechnological method using biosorbents.

Biosorbent - is carrier with microorganisms, immobilized on the surface, used for purification organic compounds [2,3].

Currently, there are a large number of biosorbents based on natural (peat, perlite, expanded clay) and artificial (polypropylene, polyurethane, etc.) materials, differing in the method of production as well as cultures of microorganisms, immobilized on its surface.

Industrial waste may be used as carriers that will be economically profitable to use, environmentally safe and technologically acceptable to obtain. Expansion the base of secondary materials for production of biosorbents will allow to use the resource potential of waste to obtain new materials with specified properties used in environmental technologies and to minimize the negative impact of waste on the environment. petroleum biosorbent carbonizate waste

In the system of thermal neutralization of the excess activated sludge a macroporous material-carboni- zate is formed. Placing carbonizate in the environment is inefficient and does not solve the problem of reducing the volume of waste. Using it as a carrier for microorganisms with the purpose of obtaining oil biosorbent will allow solwing several ecological problems at once [2].

On the basis of previous research optimal conditions for obtaining by the biosorbent by the adsorption method were determined on base of carbonizate and microorganisms-oil degraders, separated from oil-contaminated soil: dry cell biomass of microorganisms in suspension - no less than 1 1g/l, immobilization time no less than 2 hours.

As a result of experimental laboratory research samples of the biosorbent were obtained with immobilized on it surface microorganisms-oil degraders with the following parameters: amount of fixed mass- 60±7,2%; amount of immobilized cells of microorgan- isms-41±2,9%; amount of immobilized cells of microorganisms per 1 gram carrier - (2,5=0,4)-107 cells 1 gram.

The purpose of the work is to assess the effectiveness of the biosorbent, obtained on base of carbonizate, in the purification of soil and water from hydrocarbons. For conducting of experimental research by purification of water, activated sludge samples were taken from the aerotank refinery named after G.Aliyev. Sampling was carried out according to the “Method of measuring the mass concentration of activated sludge”.

Hydrochemical and hydrobiological indices of activated sludge were measured by methodical manual by hydrobiologicaland bacteriological control of the biological treatment process at the plants with aerotanks. Determination of oil products in water was carried out by the method of IR-spectroscopy and the concentration of oil products in water was calculated by the formula:

Where C1- is content of oil products in eluate; V1- is volume of eluate, dm3;

V2 - is volume of water sample taken for determination, dm3;

K-is coefficient of diluted eluate.

For conducted of experimental research by soil treatment samples of the oil-contaminated soils were taken from technological bioremediation site. Sampling selection was realized from surface layer up to depth 0,3m by method of “envelope” (mixed sample on area 20-25m2). Determination of oil products in soil carried out by method of the IR-spectroscopy. Concentration of oil products in soil (X, mg/kg) was calculated by formula:

Where C1- is device readings mg/dm3;

M-is sample weight for analysis, kg;

is total extract volume, dm3;

is volume of the extract taken for dilution, dm3;

V2-is volume of the extract, received after dilution, dm3;

Val- is aliquot volume of the extract, entered into the chromatographic column, dm3;

Vel- is the volume of the eluate obtained after passing the extract through the column, dm3.

Soil moisture was determined by drying of the soil sample up to the present mass by temperature 105±5oC and determination the difference in the mass of the soil before and after drying.

pH reaction was determined in a waster suspension of the soil using pH meter.

Microbiological control was realized by the following indices: the number of hydrocarbon -oxidizing microorganisms microscopic fungi and bacteria of the Azotobacter genus, using the method of planting on various elective nutrient media widely used in practice. Represented groups of microorganisms play a major role by treatment from petroleum hydrocarbons.

Statistical processing of the data was realized with Excel 2007 program, by calculating the average arithmetic and standard error of the mean.

Significance of difference between averages was evaluated using a Student's t-criterion for a significance level a=0,05.

To determine the effectiveness of the obtained biosorbent based on carbonizate and hydrocarbon oxidizing microorganisms a series of experimental research's on the treatment of water and soil from oil products was carried out. For the biological treatment experiment the oil- contaminated waste water was used with content of oil products 150 mg/dm3, supplied at the biological plants of refinery.

Treatment of the oil-contaminated waste water was realized in the laboratory aerotank by help of activated sludge, corresponding for use by hydrobiological and hydrochemical indices: cotton setting speed-fast; color-dark-brown, odour - marsh, water over settled sludge-transparent, sludge index 106,6±5 g/ml.

In activated sludge hydrobionts have been identified that are indicators of good work of the treatment plants, namely: Tokophzya, Lemnazum, Lecane (Monostyle) decipiens, Arcelladis Coides, Arcella Vulgaris

Arthrotardigrade, Vorticella Companula Aclosoma ten ebrarum, etc.

As control used the results of experiments on water treatment: by traditional method without addition of sorbents and biosorbents and also by use of carboni- zate.

Control of the process of water treatment during the experiment was carried out according to the physio- chemical (content of oil products, pH) and hydrobio- logical indices of activated sludge (smell, color, muddiness, settling speed of activated sludge microorganisms). Efficiency of water treatment was estimated after 8 and 24 hours of the beginning of experiment.

According to the results of research in all the investigated variants, the visual state of the activated sludge was within the normal range. But with microscopy of sludge after 8 hours there was deterioration of the biocenosis: hydrobionts activity decreased, protozoa cysts appeared, species diversity has decreased. After 24 hours of biological treatment noted an increase in activity, number and species diversity, which indicates a relatively stable biocenosis of activated sludge which is restored naturally and in a fairly short time.

No significant changes in the state of hydrobionts sludge were observed during the microscopy of sludge using carbonizate and biosorbent.

Results of experiments by biological treatment of waste water by help of biosorbent presented in the table 1.

Table 1 Results of experiments research by biological treatment of waste water

As can be seen from table 1, treatment efficiency of waste water from oil products after 8 hours made up 53,8% in variant 3 and 54,4% - in variant 2, which is more efficient than the way of traditional treatment method in 2,3 times.

An increase in treatment time up to 24 hour did not significantly improve the treatment efficiency in variant 2 ( use of carbonizate) and in variant 3 ( use of biosorbent). By traditional treatment method (variant 1) efficiency after 24 hours is increased in 3 times, which can be explained by the fact that the microscopy of activated sludge require more time for processing of organic substances, which is confirmed by microscopy research data. The use of carboizate and biosorbent will not allow to increase the treatment time up to 24 hours, but to carry out treatment in aeration tank for 8 hours.

Treatment efficiency by help of biosorbent (variant 3) is insufficient compared to the control variant 2, which can be explained by necessity immobilization, of the most effective microorganism used for oil pollution elimination.

To increase the efficiency of the received biosorbent is recommended: to select the optimal consortium of microorganism-oil biodestructors, using oil as feeding source and also provide maximum fixation of microorganisms in the pores of the carrier. Formation of the microbiocenosis on the surface of the material depends on the nature of carrier and microorganisms, the degree of hydrophilicity of the surface of the material and living cell, charge of the living cell surface and carrier, correlation of size of microorganisms cells and pores of carrier and many other factors.

To determine the effectiveness of the obtained biosorbent in bioremediation technology a series of soil treatment experiments were conducted, containing 40±5 g/kg of oil products, selected from technological areas of bioremediation.

Experimental research by bioremediation of the oil-contaminated soils were conducted in laboratory conditions in containers by volume 5,0dm3 during 3 months. In the course of the research maintained constant conditions: air temperature 20±2oC; pH of medium 6-7; natural lighting; substrate humidity 60±5%.

As control used the results of experiments by soil treatment: by traditional method with addition of struc- turer-sawdust (variant 1) and also by use of carbonizate (variant 20).

Justification for selection of components correlations of the studied substrates were existing technological parameters of bioremediation process in climatic conditions of Azerbaijan ( variant 1); literary data by use of biosorbent and also experimental data ( variants 2,3). Control of the treatment of the oil-contaminated soil during experiment was conducted by physio-chemical parameters (content of oil products, humidity and pH). Effectiveness of soil treatment was evaluated over 1,5 and 3 months since the beginning of the experiment. Results of experimental research by soil treatment by help of the received biosorbent on base of carbonizate presented in the table 2.As shown the data of the table 2, the effectiveness of treatment soil from oil products was 59,3% in variant 3 (use of biosorbent) which in 1,6 times higher by comparison with variant 2 ( use of carbonizate) and in 1,7 times higher by comparison with variant 1 (traditional method). Effectiveness of treatment by traditional method and by use of carbonizate practically no different, which allow the use of carbonizate as a structurer by bioremediation of the oil-contaminated soils.

Table 2. Results of experiments research by soil treatment

On base of conducted research by use of the oil biosorbent was determined:

By conducting of wastewater biological treatment by help of biosorbent during 8 hours content of oil products in purified water is decreased up to 53,8%, which is more efficient than the traditional treatment method in 2,8 times. Increase of treatment time up to 24 hours allow significantly improve the treatment efficiency.

By comparison with carbonizate application of received biosorbent did not allow to increase the efficiency of water treatment which may be explained by necessity immobilization on carrier of the most effective consortium of microorganisms used for liquidation of oil pollution.

3. Use of biosorbent by biological treatment of soil will allow to decrease content of oil products up to 59,3 % which in 1,6 times higher by comparison with use of carbonizate and in 1,7 times higher by comparison with traditional treatment method.

Literature

1. Белик Е.С., Злобина К.А. Исследование возможности использования отходов производства в качестве биосорбента // Вестник Пермского национального исследовательского политехнического университета. Прикладная экология. Урбанистика. - 2016. - № 3 (23). - С. 62-76.

2. Каменщиков Ф.А., Богомольный Е.И. Нефтяные сорбенты. - Ижевск; М.: Институт компьютерных исследований, 2003. - 268 с.

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